I think you need to get some sort of legitimized sponsorship. I bet this is fairly complicated.

A friend of mine did this to work as a waitress for four months in SC. http://www.swap.ca/out_eng/destinations/usa_internship.aspx Apparently she found work after she had received the visa and didn't have to report it. I don't want to do anything shady though. I guess you can't sponsor yourself (or your co-founder) for a J1 either?!