I've been researching some options myself, and FWIW, I've really been leaning towards ARB. Really it isn't much more than I've found e-locked rears for, ($900) (although I do have a non trd so I have to swap the whole axle). I think I would still use a seperate compressor for locker and tires though. The ARB seems kinda small to do tires if you ask me. I would put it in my jack bay though, and heating would be an issue as well in that case. Also in my case, I'll be re gearing front and rear when it comes to this, so I've been looking to find a deal on gears/ install kits/ ARB front/rear/compressor all at once. I think if I buy that much crap I can get a few hundred off in a deal.
More to your situation, I can't see why a couple of hundred is a big deal for the added drivability of a selectable in the snow. I have heard from a few people that they have no problems in the snow with detroits/aussies, but I think they must drive differently than me. I like the skinny pedal, and I drive to the ski hill a lot each winter. That makes selectable the only way to go, for me at least. So, 1k for arb and compressor, or 900 for e-locker, plus the parts I need to make it work in my non trd. Thinkin ARB, as it can then power the front.
'01 Taco, DD, 33's, dented armor, squeaks, rattles
'80 Pickup, 35's, locked, armored, geared, lifted, and does ok when the hubs are locked in.