http://lh6.ggpht.com/_TCSH6bqjHEM/Sj1a0cRPulI/AAAAAAAAALU/HeUqEJhUfjI/s400/se...

I followed diamond jim's lead here
I removed the seat cover and foam exposing the seat pan. The seat pan has a lot of low and high spots, to add rigidity and insure that your butt hurts after 30 minutes. Following Jim's lead I used a can of self expanding foam (the kind you get for leaky doors and windows) to build it up level. This takes a while to set so you might want to get some beer. I then added two layers of ½ inch foam to the seat pan from a blue walmart camping pad. I used 3M  spray adhesive on both surfaces of the foam and on the seat pan. A little work with a grinder and a curved sureform file gave me the shape that I wanted. Then a layer or two of polyester quilt batting (no mold with polyester) to smooth any sharp areas around the edges. I glued the batting to the foam. Finally replacing the cover. The cover was not as hard as I was lead to believe. I lined it up and added a couple of staples at the sides to keep it centered. Then I folded the front of the cover back to the middle of the seat and sprayed the top of the batting and the bottom of the cover with spray adhesive. You need to work quick here because you only have about 15 seconds to get the cover pressed down and smoothed out. Give the glue a minute or two to bite then remove the staples, fold the back half of the seat cover forward and repeat the process.
I raised the nose of the seat up about one inch as well. I cut the pillion down about half way and added an inch of my blue foam back but it might have been too much.
Tell me what you  think.
I haven't had a chance to try it yet. As you can see I am working on a DJ longshot exhaust and I an waiting on a Sportster baffle from a friend. If I was to go for a ride the way it is I wouldn't make the end of the block before being pulled over. Man is this thing loud!