This popped up on VFRd the other day, apparently, you can customize their aftermarket seats with just about whatever you want.
Colors, styles, make the seat taller, shorter, move the perch fore or aft, gel inserts, etc.
http://www.bagster.com/moduleselle/application2007/color-normal.php?lang=ukFor example:

But if you want it yellow, silver, green and red (yeech) then it's all yours.