I have the Starlight and Pelican cases for travel.
These are heavy TOUGH cases, if you firearm gets damaged during transit in one of these the carrier's accident will be in the news. You could pull these on the ground/snow behind the 4-wheeler or snow machine if you wanted or need, they're that tough.
They're waterproof, have a vent for altitude changes so you can get the thing open.
The foam replacements are a little costly if you een need any.
Starlight cases can be found at some SAMS clubs stores for about $80 to $100 (USD) just now. These have the lesser quality foam inserts. You can call direct to Brock at Starlight and order a case with whichever foam you like, a costlier alternative but it's better outfitted.
Starlight: Phone (919) 965-8643 Fax (919) 965-9177 Toll Free (877) 782-7544 (Sometimes Brock has overruns for a good deal.)
There's a dealer in Calgary, AB (The Shooting Edge Bay 4, 510-77 Ave. SE Calgary, Alberta T2H 1C3 001-403-720-4867)
Pelican cases are about the same and should be easier to locate in Canada.