Hi there, apparently it's time to necro this post again. :-)
Previously (long time ago), there was this 114MB file all_q2_textures_07_17_2006.zip available for download from justjim's personal page at University of Michigan. Several years later (ca. 2010?), directory structure was reorganized, and that file was replaced with a different one, apparently more complete, 377MB q2_textures.zip (without embedded date in the file name, but should be 04-12-2009). I also have another version of those textures, textures_05-06-2008_tga.zip (200MB).
Google didn't turn up any working links or mirrors. If anyone still has that original file from 2006 on their harddrive somewhere, I'd appreciate if you could upload it somewhere, at least for a short while. Hosting 114MB should not be a problem these days, but if you need help with space, tell me and I'll arrange something up. For the record, below are the relevant metadata to verify file's identity: