In reply to mcawle:
I'm currently reviewing the Montane Pac Plus XT Waterproof Pants [sic].
They have only 3/4 length side zips, and they lack a fly, but in other respects could fit the bill.
They're light-ish (c.350g) and surprisingly packable, yet they have the protective feel of proper winter overtrousers with a burly 150D fabric and decent kevlar kick patches. Nicely cut for movement.
They don't quite have the tailored feel of ME Tupilak pants but they're a lot cheaper and light enough to carry just in case, year round, which as others have said is not something you'd say about Tupilaks and the like.