For those of you who have experience, what would be the best method of doing it? (email, twitter, etc.)? Also, what extra info should be included along with the submission?
I imagine an email with a presentation included. You want to "sell yourself." They don't want to open an email that says "I think you should use this scheme."
They will want an entire presentation. Make yourself look really damned good and show off multiple works of your art. If you present multiple works of art, they may be interested in a different on than the one you are selling. Also make yourself available for telephone contact (or, if close, personal contact.)
It's all about the presentation, just like a job interview. Essentially, it IS a job interview, to be honest. I wish you guys the best of luck. I'd like to see some of the community's paint schemes at the track, that would be pretty cool.