If you're in the market for a speaker cab or 2, you should check out this guy on ebay. His prices are very good. Most are empty cabs (no speaker), but some are complete. I'm sure he'd build anything you wanted.
Those look really well made. I've been tempted to run my Ampeg GU-12 into a 2x12 -- it has a pair of 7591s out, which are probably capable of pushing more than they do through the single 12" in the amp's open back cabinet.
thanks for the tip, Steve! I'll have to check him out the next time I need more volume.
FWIW, my previous 2 cabs (one 2x10 for bass, one 4x12 for guitar) were bought from Dave/Avatar Speakers, and although he doesn't make the cabs he sells, I can't say enough nice things about the quality of his product or his customer service: