Well, aren't I silly? I knew what I wanted had to exist, but my searches just weren't coming up with anything good.
I think the sea to summit pretty much nails it. The other ones are great, and I like the Marmot Kompressor, but for packability, the Sea to Summit wins. It will spend more time packed away than in use.
Thanks all for the great suggestions! If a mod wants to move this to the gear section, that would be fine.