I own an Epi T-110UL, as well as an EA Wizzy. Both would be excellent options fitting the criteria which you have described. The T-110UL is a bit smoother sounding, has beautiful silky high end, and actually sounds deeper than the Wizzy at low volume. Its main limitation is that it just does not push that much air. Still, if you don't need a lot of volume, it sounds just beautiful. The Wizzy will not have the same sparkly type high end (not having a tweeter, and all), but does have plenty of articulation up high - especially for upright. It is more midrange present, and makes the Epi sound a bit scooped in comparison (which it is). Even though EA admits that the Wizzy has a bit of an upper midrange accentuation, it is still a very accurate cab, and certainly moreso than the T-110UL.
I have heard the Bergie HT112 (and the EX112), and agree that it is a very good sounding cab. Of course, you say it is too heavy, so we'll keep going...
You may want to read some of the threads on the Low Down Sound 2x8's. These are very nice sounding lightweight cabs. Although I have not heard their 2x8's, I have heard their 3x8, 4x8, and 5x8 (in addition to several other cabs). These cabs have tons of low end, and pretty good articulation, in a more old school, warm kind of way. They do not have the upper midrange presence of something like an HT112, though.
Personally, I'd think that either the Epi T-110UL or the Wizzy would be your ticket. If you really like focused, present mids, then I'd steer you towards the Wizzy.