Been looking for places that accept pets. In case others are interested, here is the complete list of accommodation listed on SJ that accept pets, sorted by nearest ski area:
Niseko Hanazono http://www.snowjapan...han/freedom-inn
Niseko Grand Hirafu http://www.snowjapan...ly-condominiums
Rusutsu http://www.snowjapan...u/hotel-romulus
Appi Kogen http://www.snowjapan...i/pension-mutti
Zao Onsen http://www.snowjapan...ata/lodge-scole
Houdaigi http://www.snowjapan...chalet-la-neige
While World Oze Iwakura http://www.snowjapan...ra-resort-hotel
Tanigawadake Tenjinda