Interesting idea, but I'm not sure it's going to go anywhere.
For one thing, you'd need something to play. And I know that the level of skill here is good, but I don't think it would be possible to play a lot of MaestroRage's stuff, or for that matter, any other classical composer on the site. Secondly, I haven't seen anyone opting to play a stringed instrument yet (not including guitars, I mean things like violin, viola, cello, contrabass), and seeing as the violins are usually the biggest part of an orchestra, it could be tricky to arrange with none or few of them. I also haven't seen any woodwinds. So really, this is a rock band with a triangle and a small brass section.
I'll keep tabs on the thread, though. Good luck.
By the way, I play trumpet, but you seem to have a few of them already.