I like the comfort of the 1290 seat for the most part, but after 1-1/2 hours I get the Monkey Butt, and can't wait to get off. Has anyone tried one of the seat cushions you can strap on the outside of the seat? I believe they sell them as either air inflatable or in gel, but am not sure if it would help that much if the problem is just my 60+ year old butt.

I haven't tried the powerparts seat yet but some peeps say it's better.
Doesn't bother me that much when I'm by myself as I tend to move around a bit, when the missus is on the back I have the same issue as I sit still.
My mate who does long distances has a gel seat on his (different bike though) and he rates it very good.

I have used a sheepskin cover on many a bike and many an occasion. The difference is night and day over a seat sans sheep. I have also tried a air bladder system and it was better than without butt it tended to feel too wiggly. I highly recommend the sheep skin approach.
Anti Monkey Butt powder is always in the panniers on any multi day tour. I don't leave home without it.

I always struggle to find a comfortable seat. Being close to Corbin I typically rider over and get a custom fit. Getting the right shape to prevent pressure areas is key. I got the Power Seat and modified it myself by taking off the cover and reshaping the foam. I removed about 20mm primarily from the rear and made it more 'butt shaped' shaped. The cover staples back on quite easy, and you cannot tell it has been modified. I now find it very comfortable. I recently ran into this site, and ordered one to try http://www.bumbags4bikers.co.uk/ I don't need it on the 2190, but I am going to try it on my Tiger. Another thing that makes a huge difference is underwear. Seamless stretch materials eliminate folds and seams responsible for dreaded monkey butt