a not to costly sugestion for you would be to continue the garage thing and just get a personal heater/ac nice smal 1foot by 1 foot by three inches you can get them at wallmart or kmart for like $20 in the winter put it on warm and attatch it to his crate on the back side to blow warm air into the crate and block it off so he can not eat it with wood .. and winter time put it on ac to cool him off ...

now if you don't think this will work then you could go with a two inch tray you can build for under the crate that will not be accessable to the dog and you can put a heating blanket under that for winter and several ice packs under there in summer time.. either way or one will work... and this way no hastle in moveing him to an unfirmilier place...