Wow, I definitely don't have this problem; I can't get enough of the heat! My old ride didn't have heated seats, and frankly, I'm converted - so much so I'm trying to convince the wife to let me install a Bench Radiator in the house!
But for your situation... would something simple like putting a cushion on the seat before you sit down solve the problem - helping to insulate you from the heat a little? Granted, the last thing you want to do is be held up too high in the seat by an awkward cushion...
It's just a thought.
Sam.