You might want to look at Hakuba as well. Hakuba is on the main island and only a short trip from Tokyo. Like Niseko, it gets a ton of snow but the terrain is a bit steeper. There are 9 resorts within 20 minutes of Hakuba. The snow in Hakuba isn't as deep typically as Niseko, but its still a boatload of snow. Far more than you'll be used to.
There's a great place to stay called Hakuba Powder Lodge run by a guy on the TGR forums, fattwins. http://www.hakubapowderlodging.com/