Why specifically TrueHD? As has been discussed a number of times recently TrueHD seems to be the least of the HD audio formats. Every disc should have at least one of the HD formats on it, be it DD or DTS.
You can also look for films with native PCM soundtracks - there's quite a few of them. Highlights out of the ones I own are: PCM:
2001, 3:10 to Yuma, Blood Diamond, Casino Royale, No Country for Old Men. Dolby TrueHD:
Batman Begins / The Dark Knight, Blade Runner (5 disc Region Free US import), Transformers