Who says THX 1138 is a niche film? Thomas Schrantz (A.K.A. Redbeard Math Pirate) knows about it:
http://www.flickr.com/photos/redbeardmathpirate/4255551875/in/photostream/
"Parts of THX-1138 were filmed in the Frank Lloyd Wright designed Civic Center in Marin, CA, although it was heavily modified through special effects, especially in the Director's Cut. [Taken on March 12, 2009] [Civic Center, San Rafael, CA, US] [Canon PowerShot S2 IS]"