You can ski park on shitty mountains anywhere, but you can't ski the best mountains in the world everywhere. Take a trip to the top of Aguille Du Midi, Grande Montets, Brevent and Flegere and you will have some of the best days of your life!
Grand Montets had a small rail park with no jumps when I was there a few weeks ago, but again, it's not really a place to ski park. Get a guide to ski you down from the Aguile and you'll have a great time. I thought Les Tour (Balme) was good for casual powder skiing and I ate the greatest sausage I have ever tasted at one of the restaurants there.
GM park now has small kickers. I had one run on them, they're OK, don't expect much. Drive to Verbier or Avoriaz if you want to ride park (one hour each).