Since larger solutions (an upright, an old Earthwood-class fatso, even a conventional ABG) seem to be out of the question in your case, the only acoustic micro appearing to be designed for remotely decent acoustic volume is the Aquila
Invalid Link Removed. It's about as big as a classical guitar, and like those it has a very thin top. Comes with their ThunderReds. 23.6-inch scale for the "12" (frets clear of the body) versions, 26.4" for the "14" models. I'd expect it to sound even louder with Pyramids or Silverbacks on (the 14s would probably be too long for these).
A cheaper alternative would be to convert a classical guitar, and slap a Silverback set on it. I'll spare you the math, but extrapolating from the similar
Pyramid set and taking into account the larger gauges of the La Bella A and E, I'm fairly confident the total tension of a bass uke set would not exceed that of an extra-hard classical guitar one by too much, IOW the neck should take it. If you took that road, the bridge would need reworking to accept ball-end anchoring, and the strings themselves may not be long enough if the "25 inches" is to be taken literally, in which case a 7/8 classical (24+ inch scale) would be needed. On the plus side, it would have a less
monstre nut width (48mm vs. 50 or more).