Have you checked out the pete millet page? his Jonokuchi amp looks neat, and has been getting good impressions.
http://www.pmillett.com/Jonokuchi.htm
The starving student is another popular option.
If you look up "11ms8" on this forum you can find an older amp that is still available in various levels of trim. Requires lots of mods & tweaking (which you can find in that thread) but that was a very fun build.
Bottlehead CRACK amp is another possibility, but really more for high impedance headphones. Dunno if that will work.