This sounds like a brilliant idea. I hope that you are also including homework assignments that cover (1) communication skills (especially WRITTEN communication) and (2) personality. In my experience, those two areas are far more critical to success than raw coding skills. Also, everyone should pass the "no assholes" test, if there is such a thing.

I hope that you expect the same amount of prerequisite work for all of your candidates (marketing, finance, sales).