The Guild B-30, B-30E(w/Fishman Transducer), B-50(older model on which the B-30 is based), Ernie Ball Earthwood(if you have upwards of 3000.00US to spend) are the ONLY ones that are playable and can be heard w/o an amp w/banjo, pipes, fiddle. etc. ANYTHING else is CRAP! Don't get a Dean, Taylor(though they LOOK good they're CRAP in an acoustic setting), Washburn, etc
None of the ones mentioned can be heard w/o some sort of an amp...so, what's the point!? It's about body cavity size and the Guild and Ernie Ball are the only ones with enough to do the job. The Guilds pop up on ebay now and then and can be had for under 1000.00US including shipping.
Have used the mariachi type and the previous poster is right...they're a blast once you adjust to the limitations. Try using some Jim Dunlop fingerpicks to give you some extra volume. I'm, also a finger-style guitarist so it was a minor adjustment to transfer the fingerpicks to my bass playing.
The Guild bass is based on the F-50 6 string, but it's 6 3/8" deep instead of 4" at the lower bout and is braced a little heavier. If you do decide to get one try to get one w/t one piece saddle as they are a little more loud and crisp.
PS: Hohner made one years ago and I heard one once, but doubt you'll be able to find one. They're even more rare than the Earthwoods.