I haven't run into a cap yet. The only annoyance, though, is that all created players are rookies, which bothers my OCD. I'm solving it by editing existing players with the right amount of experience (who are roughly the right height and weight - it's like a really tedious jigsaw puzzle) into the players I want.
I think I have a cool concept, and I started on my roster set last night. Just to reiterate, if anyone wants to team up on this, it will drastically increase the chances they'll someday be done.