I've only played three acoustic bass guitars that came close to working well as acoustic instruments. They're all very large, and a bit clumsy due to that. But then look at the physics of what you're trying to get it to do. The flat-top guitar isn't the most effective way to pump air. That's why most early jazz guitars were arch-tops. Now then, a double bass (upright, string, doghouse, whatever you call 'em) is big enough to do the job, but just barely. Asking a small bodied acoustic guitar design to do the job of creating low notes with authority and volume is IME and IMO just asking too much.
The way acoustic instruments work is that the strings make the bridge vibrate, and that drives the body to pump air. To get more volume, you need to move a lot of wood so you can move a lot of air. That means a big sound board that's flexible enough to vibrate but stiff enough to not fall apart. To get low notes with authority, you need to be able to create big waves, which again means a big soundboard.
The three I've played (in order of utility) are the big Guild (they made two, and the smaller one is just as problematical as everyone else's small one) B-50/B-30, the Ernie Ball Earthwood, and a very distant third is the Tacoma Thunderchief. There are some other designs I've seen that might work but I don't have any experience with the great big Martin (all the Martin ABGs I've played were smaller ones), the Taylor (designed I believe with Mike Tobias' help?), and the Azolla arch-top ones.
So, if you want a truly unplugged experience, resign yourself to a large body. If you want the sound of an amplified ABG, then get one with a really good pickup system and don't worry much about the acoustic sound. As for me, if I gotta take the amp, I'll just take one of my solid-body electric basses too.
John