Let me add some response to the posts already made to help narrow things:
GoLite Dawn - Very good, except for the lack of compression straps, but the volume could very well make up for that.
Gregory Advent Pro - Possible, but somewhat more features than I really want (weight), and the capacity is a little more than I need.
ULA Conduit - Very good, and very close to what I'm looking for. In actuality, I'm actually looking more at the ULA Relay, but it lacks a padded waist belt. One or the other are very high in the running.
MLD Prophet - Impressive on paper, and the customizable options are nice, but it's hard to picture what the prophet 20 or 40 look like, as there are only pictures of the 30.
Six Moon Designs Essence - Possible, but I'm just not a fan of the design. I much prefer a standard pack bag with a drawstring closure.
Golite Multi-Sport - the original pack that spawned this thread. I experimented with my current "day" pack (a Golite 24), and I was just barely able to squeeze everything in, but it was a squeeze. The big thing I wasn't impressed with was that the pack didn't carry like a pack, but more like a sack on a string slung over my shoulders - not something I would look forward to over 80 miles in a weekend. So, it was back the drawing board, and so far, things are going in the right direction.
Thanks for all the suggestions!