tTat island lake one is a bit pricey, looks good though
Whistler was $1150 for 8 runs (I'm assuming that's no lodging, meals, or anything). While Island Lake is $2500-$3000 or so in March for 3 days. Including lodging, meals, probably 8 cat runs each day, etc. etc. etc.
Every winter is different as far as snow goes, but I'd say Lake Louise had more consistent snow last year than some of the others. It's that much farther north vs. Fernie and Nelson so when they were getting rain it was getting snow. You might want to try to book a trip to Lake Louise or Kicking Horse and then find a heli/cat place close by. For a relatively cheap cat day check out kpow.ca it's the closest cat skiing to Calgary, obviously not going to have the sheer volume of powder that some of the interior mountains will, but I've had plenty of fun powder days at nearby Nakiska, and with them only running smaller quantities of people there should be plenty of good snow there all year long.
I'm sure there are hundreds of places near Kicking Horse and Revelstoke. I've got a heli-cat guide somewhere I'll have to dig up and get back to you.