I never tried more than 6 in a launch wing, because I also added no more then 6 paths to a single fighterbay subsystem. AFAIK that limit of 10 is a matter of the Source Code.
Also, to be honest, where is the need to launch so many at a time ? Can you even group a wing with +10 ships in FRED ?
If you want to have a massive one-at-a-time lauch, create multiple wings, split them up on different fighterbay subsystems, and via fred you can even specify which fighterbay-path they shall take.
Story wise, if you have a model with limited fighterbays, it would be a bit unrealistic to launch so many at a time. Just my 2 cents though, I don't want to hurt your imagination
