I've heard of a lot of guys going for very strange application sites..tops of feet, thighs (assuming they are hairless), and the strangest one, application to the asshole. Dude honestly felt that since the skin is thinnest on areas like the tops of the feet and that thin layer over the asshole, it would result in a greater rate of absorbtion.
IMHO, stick to the areas with little fat, as I'm sure you already know. Arms, shoulders, etc. For awhile I was applying isopropyl right before the transdermal, the thought behind this being for the alcohol to open the pores for an increased absorbtion. There are guys who swear by this, I didn't notice much of a difference. It really eventually becomes a preference thing.