IMO, TA just deflates my already nearly non-existent butt... Then again, it's not that hard to supplement her workouts to keep that from happening if you really enjoy the rest of the results you're getting from her workouts.
For me, there are only two workouts that I do that seem to build my bum without bulking other areas, but my thighs have never been a huge issue.
1) Stair-stepping machine -- no matter how under or over-weight I am, this is always a magic bullet if baby wants back
2) Surprisingly, when I am consistent with power yoga and/or vinyasa flow (meaning at least 5X a week), I get the best butt ever... I say surprisingly because even though I'd heard about yoga butt I never really believed it until I saw what it did to me -- colour me thrilled!
(Mind you, I also tend to do the pretzel exercises from Callanetics daily, so that could be helping to send everything to the right place.)