Assuming you're not looking for discs, I asked a similar question in this thread:
http://forums.thepaceline.net/showthread.php?t=210386
Most of the options that were proposed were steel, but there were a handful of alternatives.
There's also the (non-repeatable) issue of manufacturing variability. Weisan-pal recently said that his 2012 Giant Defy (aluminum) frame could easily fit 28's and possibly 30's or 32's. Beeatnik's CAAD10 fits 32's; mine could barely clear 28's. So be wary of any anecdotal evidence...