While discussing the best way to beat Geek's Longplay record (76 hours, 80GB) on IRC, I started thinking about doing Fallout: New Vegas.
However, this game, along with several other modern RPG (and RPG-hybrids), feature choices that make quite a difference on the gameplay. In the Fallout games, you first have to select what type of character you play (heavy weapons, handguns, melee, etc) and during the story, you can alter the story quite significantly with your choices (F:NV have several quests that are only availabe if you side with certain factions, and you can't side with several).
This presents a problem for a Longplay, especially of an RPG, which is often long just for one playthrough. Doing several to get all the differences depending on choices would probably double the size and length of the video.
So, I was wondering if there would be any interest in doing a longplay "interactively". That is, before starting, there are a number of polls to let the viewers select the basic premise, and during the gameplay, at key moments, the viewers get to choose what path to take.
The latter part could either be done by publishing parts continuously during the playthrough, or by describing the situation (without spoilers, of course) in the poll.
I'm primarily thinking of New Vegas now, but there are other examples as well, such as the Dragon Age, Mass Effect and Infamous series.
I think this could add a new dimension to longplays, if people are interested in contributing. Otherwise, I'll probably just do it like I want. :)