OP, I'm still not 100% clear on the exact configuration of the space granted by your generous manager for a cab, so vetting the dimensions (including accounting for handles, rubber feet, etc.) is on you:
I own and dig a couple of the bigger MAS cabs. I've played the MAS 16 and MAS 18 over a couple of visits at Mike Arnopol's place -- we played them at length with different amps and instruments, but I don't own and haven't gigged those smaller cabs (though I do own and have gigged a MAS 46). My impressions:
The MAS 16 is a great little cab -- more than adequate for your in-RV playing and for reasonable volume jamming with a group. It's clear and deep, with good fidelity (sounds good with recorded music), and goes louder than you'd think (you could use it in place of a decent 1x10). That said, for electric bass, I prefer the MAS 18 and, if it's within your budget and will fit in your space, it's the cab I would suggest. It goes a bit deeper than the MAS 16 (which already goes fairly deep), is similarly clear and detailed, and is as loud as two of them. More than that, it feels and sounds "meatier" with electric and has more of a thump/bounce. Put another way, I'd rather play electric bass in a trio setting with a 18 than with a 26 -- I haven't heard another cab the 18's size that can equal its combination of clarity, true low-end extension, and volume potential (I'd feel comfortable using it most places where I'd use a good 1x12).
I've tried the Shuttle 3.0 8T, mentioned above, a few times in music stores with electric and once with doublebass. Not a lot of real deep low end from the small cab or the 3.0 head (which was optimized to get the most out of that generation of Genz combo cabs) but, as was said, louder than you'd think and more open/less boxy sounding than the majority of small combos I've heard. Sounded better and more natural with doublebass than I expected it to and I can think of a couple of smaller venues in which I think I'd enjoy it with electric (though it wouldn't be my first choice with a low B). A used one in good shape (or a new-old-stock one, if you can find it) might be a nice find.
Here are specs on the
MAS Bodai 28 - Bodai 38 Special and 18 Discussion and on the
MAS 18.
The MAS 18 (and, I think, the 16) are somewhat wedge-shaped, which might help with your space (I think you'd have to turn the 18 -- and maybe the 16 -- on its side), but, again, it's on you to verify that.
You'll find some discussion of the MAS 18 here:
MAS 18 Review and, on the DB side, here:
MAS Bodai 28 - Bodai 38 Special and 18 Discussion
Hope that helps.
