And finally...
I test rode an 2005 XS (14") Ellsworth Truth on Thursday and loved it. The bike shop owners were super nice -- one of them brought me his wife's bike to test. I never thought I could fit properly on such a small bike, and to be honest, I still feel weird about it. But other than needing to raise the seat and push the saddle back a bit, the fit feels good. The Truth's virtual top tube measurement is 21.3" -- almost the same as my GF Tass, which is 22". My Tass has a 70mm stem, so I could make up the difference by putting a 90 on the Ellsworth. I'm also concerned about bobbing, but the bike I rode is set up for a 130lb. rider, and I'm... not 130 lbs. I want to read more about the rear shock system on the Ellsworth site, but my mechanic says that it's just a matter of setting it for my weight.
I originally thought that even the 14" Truth wouldn't work, because the standover heights published by Ellsworth are the same for all frames -- 28". But the LBS owner said that in 2005 (but not in 2006), they made the top tube differently just on the XS in order to give it a lower standover height. The frame they offered is a 2005, so they're willing to knock a few hundred dollars off the price.
~Cari