I was sitting in the sauna this weekend with a helicopter pilot from England. He's skied the French alps a bunch, and Fernie and the Rockies one two separate trips. He said there's no comparison, he loves it here.
My personal favorite is Fernie, but I haven't been to revelstoke or kicking horse. Fernie is a really relaxed town, and the mountain has great bowl boarding with lots of powder and lots of trees. Unfortunately it also gets slightly warmer weather so that could be a crapshoot. The rockies create really weird weather patterns so one resort could get dumped on, while another 30 minutes away could be getting rain or nothing.
If there's any way you could book the time off, book your flights, and then do the rest on the fly my guess is you'll be able to find great snow at the last minute. I'd fly into Calgary and any of the resorts we've been talking about so far are within a 4.5 hour drive from Calgary airport.
I'd strongly suggest hitting up multiple resorts. Lake Louise is two hours from Calgary, Kicking Horse another hour or so, and Revelstoke another 1.5 past that. You could do a couple days at each resort without having massive drive between each date.
And yeah, let us know where you choose to go you might get a local to show you where the stashes are on each mountain. I've found some places on fernie where you can have almost an entire run in pretty much untouched snow several days after a big storm. Lake Louise gets used and abused far quicker than Fernie. Again, not sure about KH or Revelstoke (I refuse to call it Revy! lol)