Sheepskins really do work. I grew up on a sheep farm and we used them for seats on all our tractors and everything. They are not hot and are basically an insulator to keep you from sweating and offer more padding. A bunch of people at st.net swear by the seat covers from some alaska company.
the sheepskin really looks buttery and i bet its nice and cool. I might have to toss my gel. It gets really really hot if I leave it out in the sun for too long. Its like I'm commiting scroticide when I climb back on my bike.