Just got word that Guru3D.com are looking for beta testers for a new version of Q3Bench with support for Return to Castle Wolfenstein! Here's what their saying.

I've sent a working "beta" copy of a new version of Q3Bench up to the boss. This one will work for all versions of Quake3, as well as RTCW.

For both Q3 v1.31 and all versions of RTCW, there are not any built in demos. If you have an older version (or copy of one) of Quake3, Q3Bench will add in the built in demos.

Q3A Beta 3 - Testers wanted @ Guru3D.com