I'll add the Tacoma Thunderchief and Boulder Creek acoustic bass (the one with the cedar top). I've owned both, I think the Boulder Creek might've been louder, but the top reference soundhole might've just made it seem that way, the Tacoma DEFINITELY sounds and plays considerably better. I play a fretless Thunderchief with Rotosound TruBass strings set up with medium-high action for old-time string band/campfire jams in lieu of an upright (just couldn't justify owning a doghouse anymore). It does the job very well, but I do have a K&K Pure Bass pickup and a Phil Jones Bass Briefcase for competing with percussion or heavy-handed flatpickers. With responsibly picked acoustic guitar (when playing with me, I usually offer my Gibson L-00 to aggressive pickers), a fiddle or two, and open back clawhammer banjo it's more than sufficient acoustically. I'm pretty sure Tacoma's budget import line, Olympia, made a Thunderchief variant, and I would think they'd be very similar to the real deal, but the thin solid wood construction and super-thin finish on the US model seem to be a big part of how loud and good they sound.
I've never played one, but everyone says the old Guild big body basses are as loud as or louder than the Thunderchief. They're 32" scale and probably a smidgeon easier to play.
An outfit called Lamont guitars is now making a model called the Flatback, which is essentially a modern, (more) affordable Ernie Ball Earthwood. I've played an Earthwood, they're THUNDEROUS. The Rigel Acoustabass is also available, they're really big and according to everyone as loud as Earthwoods with a more upright-y tone, it'll be my next bass purchase.
@bholder is right, as far as I'm aware there aren't any especially manageably-sized or especially affordable acoustic bass guitars that will truly hold their own unamplified. Aside, presumably, from the models bholder mentioned, the Lamont, and the Rigel, all of the basses mentioned thus far are out of production, and all are somewhat hard to find.
All, even upright, are limited when it comes to percussion and such.