I don't have any house rules per se, but I've pondered adding two features: goals and triggers.

Keep in mind, neither one of these have really been fleshed out.

Goals are pretty obvious: what is the group looking to accomplish?  What are the individuals working towards?

Triggers could be encounters, events, or choices that take the DS in a different direction.

If you accomplish your goal, the DS either ends or you may change your approach and start a new DS (with new goals, potentially).

If you "activate" a trigger, the DS ends and the scene shifts gears, usually into an action sequence or a new DS with different circumstances.

For example, lets use the classic example of the heroes infiltrating the villain's mansion searching for dirt they can use against him.

The group's goal is pretty simple: "find dirt on the villain."

But perhaps one of the players passes you another goal: "find evidence that the villain was behind my father's murder."

Ok, so now you (the GM) know what you are going to be dealing with.  Call for approaches and you are off to the races.

But to keep things interesting, you've secretly added a handful of Triggers to the mix:

• Discover the villain is romantically involved with one of the hero's connections.
• A henchman who has a vendetta against one of the heroes.
• Members of the Rilascre moving to assassinate the villain and a guest (someone the heroes might want to protect).  (You've decided this is a timed trigger: things start blowing up on Raise 2).

So here's how it works (in my head anyway).  The players explore the mansion working towards their goal.  During their investigation, they come across trigger 1.  At this point, the group may choose to ignore it, or focus on it (changing the goals of the DS and potentially allowing a new approach).  But they ignore it.  They also, through stealth and clever choices, avoid your henchman.  If they had encountered him, there would have been a fight (cue action sequence).  That leaves the timed trigger.  When everyone has 2 raises left, BOOM!  Again, this changes the circumstances of the scene and you might permit a new approach if the group goal changes.

Like I said, it's only about half way there.  I feel like it's missing a component to tie it all together.  But the core idea is that Triggers and Goals are meant to be points where one DS ends and either another DS (or other sequence) begins.  Goals are either completed or change.  You could even rule that actions outside of your goal cost extra raises if you really wanted to.  Triggers are traps the heroes hit that immediately change the focus of the scene in ways that may be out of the players' control.

Page 188, it's worth remembering that if you use a raise to try something and it doesn't create any significant story progress, you get your raise back. The example given is a PC plying an NPC for information; if the NPC doesn't have any juicy info to give, the PC gets the raise back.  That should help some.

But if it's still not enough, then as a GM I would experiment with separating each of your planned 'dramatic scenarios' into two and see if that helps. Just insert some new development into the middle to justify it. Let's use the ballroom scene from the quickstart as an example.  Instead of having it be one scenario, you could announce "this will be a scene in two parts; early evening and late evening." Players then roll for "Ballroom scene; early evening." They do stuff. After everything seems to have played out, you say "Unexpectedly, the page announces "Signore Giovanni Villanova".  A hush falls over the crowd. While nobody moves initially, you can practically feel everyone jostling for position with their eyes."  Now the players reroll, and they and the NPCs try and accomplish other things. 

I agree with the last post that you can certainly separate out your dramatic scenes into smaller chunks, therefore preventing too many players to run out of raises before you get to the end.  I don't think you want that - if you can help it.

I haven't run into an issue like this yet with my groups, but I also pull heavily from other games regarding how I run things.

Primarily, here's how I handle Dramatic Scenes:

• The Dramatic Scene ends when the party changes "locations." A change of "location" would remove the group from the Dramatic Scene in some way.
  For example, if the group is at a party, a party member sneaking away to rob the noble would not be leaving the Dramatic Scene, but if the party were to all leave the manor and head into town, the Dramatic Scene would end.
• The Dramatic Scene ends when a specific event occurs. I usually try to keep Dramatic Scenes relatively short (the group often makes them last longer) to ensure that players can do interesting things and keep things moving.
  For example, the group was attending the party for Alberto Lucani's daughter's birthday. Another noble wanted to "celebrate" the young woman reaching a marriagable age, and as said noble was causing problems for the group, they decided to pull strings to attend. They all had the goal of picking up information, so I mentally set things for "Once they complete X, Lucani shows up and forces a new scene." 
• The Dramatic Scene ends when combat or similar action begins. This is self explanatory: if the scene turns into a fight, cue combat rules. I've considered granted bonus raises to players who still have remaining Dramatic Scene raises left unspent, but never got around to it.
  After the Action Scene, if the scene transitions back to Dramatic, get approaches and continue on as per usual.

One thing I have noticed, though: some players STRUGGLE with Dramatic Scenes, while others take right to it. It's the difference between players that are used to (and enjoy) narration and players that expect the dice to tell the story for them. I've had both types during my now-failed online game, and the ones who didn't have much experience or skill with narration where the ones who struggled here.

I went to a spreadsheet for that and started building a Situation->Approach->Consequence->Opportunity List. It gets a lot easier to keep the story flowing if you have a cliff notes of possible paths. I had 44 possible approaches (I know I'll end up adding more as I run sessions), 15 general Consequences and 5 possible opportunities.

This is my first post. Just got back into the game with 2e at Gen Con. I too would love to see the Situation->Approach->Consequences->Opportunity List you have developed. I like the idea of taking the DS and creating opportunities that can lead to "nested" DSs or sub DSs. I am just in the process of character building and campaign plotting, so any insights from those running/playing is always great to read.

I always felt that Dramatic Scenes are designed to lead to Action Scenes.  I am going to use Dramatic Scenes to segue into cool Action pieces which is a standard trope of Swashbuckling.  That said, it's not really a fix/house rule for it, just my interpretation.  

I never understood why Dramatic Sequence should have only one round, but time span it has depends on situation. 

I once used Dramatic Sequence to describe events of day. It was one roll, but each raise gave lots of stuff done. For me, as very experienced storyguide running games for 3 decades, the varying time span is really nice thing, but I recall how frustrating it was when I started to run games in White Wofl Mage 2nd edition. I do understand it  is hard for less experienced storyguides and players, and some suggestions should exist. There are some good rough guidelines found on other systems with similar idea of time - like Fate or Dresden RPG - which can be useful for 7th Sea.