I'd go with the ball joint uppers given the winters you'll see up there. Uniballs are generally a 15-30k mile maintenance item for most street driven/mild off road rigs... That said, they're not too hard to replace in most UCA applications. Fwiw most folks in my local crew here have swapped out to ball joint uppers from uniballs because of the maintenance intervals, we chose to get some ball joint UCA's vs uniballs for the same reason.
Your own instinct and rho's is spot on - but I'll confidently push you AWAY from uniballs as they are a performance (racing) piece of kit and might be a disaster for your application.
Let me tell you why (and my perspective might be shit ;)) the uniballs REQUIRE maintenance and they are unprotected from the elements.
Shit gets dirty, and squeaky, and nasty, and once dirt gets in, there is no way to remove it without pulling it all apart and rebuilding (AFAIK).
Call and talk to the guys @ DirtKing (not sponsored but bought their parts), King Shocks (not sponsored but if you're building a LA Lexus, you need their input), and talk to Ben @ FilthyMotorsports about suspension and you'll sort it out pretty quickly. The biggest challenge is figuring out what it is that you want the rig to do! After that, it's all execution and getting out the camera ;) Ping me if you want more info on contacts (I'm still building my rig)
Cheers,
DP