He probably likes the coolness of the hardwood floors, so try a cooling bed. The last site (below) seems to be down at the moment, but it has sort of a doggie shaw that fits over the shoulders and down the legs to put padding on the legs where you need it. Canine cooling beds: http://www.dog.com/itemdy00...

I hope that a cooling bed works for you, but if you need something more for the calluses look at the DogLeggs on ( www.dogleggs.com ). They also have a version that goes down to the wrist.