Not a DCT owner, but the better question would be how much to replace a worn clutch. Launches shouldn't cause any more damage than a worn 1st gear clutch (there're 2 multi-plate clutches in there), but I don't think it's an easy (or cheap) job since it requires removing and opening the tranny. I wouldn't do any more hard launches if I were you.
I haven't read about anybody replacing a DCT (or even 6MT) clutch yet, so I doubt you'll get a definitive answer on this, but speculation is fun
. And I'm sure you'll get better answers than mine. Good luck.