I'd very, very much have something like this for my motorbike ... even though at $175 the ski version would be the second most expensive item of gear after the helmet, and then only by a few percent. It'd be well worth it for the safety factor of not having to keep glancing down at the instruments, which on a naked-type are quite a bit further out of the typical eyeline than on a supersports or in a car. Plus you could add a few extras besides the speed, fuel and basic "idiot lights" I have - revs, gear indicator, simplistic sat nav interface (next turn warning), rough fuel range, remaining ammo and oil slick dispenser charges, and maybe a smart speed indicator that uses both the GPS and normal speedo to account for errors or dropouts in one or the other... with very little extra cost, unlike the trouble of buying, mounting and plumbing in a physical unit.
Infrared camera or some kind of peripheral vision extension system (with, or used exclusively for, outline highlighting) wouldn't go amiss to aid with mirror blindspots and poorly visible cars/pedestrians/obstructions. Winter is a shit time to be riding simply because of generally reduced visibility (darkness, misting) mixed with reduced evasion ability (less tyre traction, and poorer physical mobility as you're got up like Bibendum) and improving the former one would mean less reliance on the latter.
Have to be careful to get the illumination level right though, or have it adjustable / have an ambient light sensor so it can be seen easily in daytime but not be distracting at night... unlike on my actual dials where the high beam indicator lamp is so bright it almost drowns out the headlight itself. Suppose this isn't so big a problem for skiing, though

where you can probably just get away with a simple non-backlit mono LCD.
I want to sign the "WE NEED MORE SSX" petition by the way. It's the last console game I was actually much cop at / played very much, and the last one I really played competitively against family etc. (Well, OK, either Tricky or SSX3, can't remember which. The one with crosscountry skier wierdos in it as well as boarders

) --- It'd have to go all out on the music licensing though, as it will have to include the tunes from all previous games to prevent someone getting upset. I, for example, would be far from happy to be without the original Finished Symphony, Shake What Ya Mama Gave Ya and Song For Dot from the first one.
A well balanced semi-arcade interpretation of an inherently (PUN ALERT) cool sport, with that right mix of easy to pick up, hard to master that also made Tony Hawks good for a non-skater (and non-snowboarder) and a fantastic visual style that made the PS2 seem even better than it actually was. Primary coloured lights on snow and ice tunnels down something the size of Everest... very yes. Give that kind of sensibility free reign on PS3/X360 or the eventual successors and see how it comes out.
Or just port a cunning conglomeration of original/tricky/ssx3 onto the Wii, co-opting the Tony Hawk skateboard peripheral or the Wii Fit balance board, and be done with it. It's at least as powerful as the PS2, right?