In reply to paulh.0776:
> Thanks Dave, I guess the weight is the big issue, they do look a lot more solid tho. and would take a big impact...
Not all ski helmets are the hardshell-insulated-stormtrooper style construction though. My own isn't much heavier than my old bike helmet and has reasonable amounts of venting.
The issue that I suspect you would have is that they tend to come down further at the back of the head. This makes it quite uncomfortable to be looking up for long periods.
A multi activity helmet as the others suggested would probably be the best compromise if you can find one the right shape for your head. My wife climbs in a Simmond Calcite Light which claims to be suitable for all sorts of things like cycling and skiing. The WC 360 or Petzl Meteor III would also be worn looking at.