Hi David,
since you've asked to join with application ideas too, here's one of them:
I think it'd be cool to have some IDE (for Scala, Java or possibly anything) that would access a project sources using Git, modify it and push it back. At the same time it would be connected with some online service (eg. CloudBees) so that the application can be compiled and deployed. It'd be really handy in case something bad happens that needs an immediate fix and a developer is on a vacation or somewhere without his laptop, but with an iPad or iPhone. The idea is to have it all somehow connected and possibly to have an access to a presentation compiler somewhere on the cloud...
I'm not sure this is a kind of thing that Visi is intended for, but I want to share it anyways.
Jan