At first, I also wanted to have my seat customized(higher, flat, wider and other foam), but I've done 10.000km so far and I'm happy with it as it is , for now. Look in this Tenere section and search for Tenere-Doug, who runs a Khaki Tenere and had his seat done. Looks good and comfy, there was also an adress were he had it done(in the U.K.). Here in Holland we got Ray, who has done lots of seats, also one for a Dutch Tenere rider: look under
www.rayz.nl under "voorbeelden"(=examples), where there are lots of pics of customized seats(for all kinds of bikes, but mostly for allroad and offroad bikes).
Greetz, Hans.
P.s.: enclosed two pics, the first seat by Ray, the second Tenere Doug's seat.