I picked up a full set of tan seats out of an '82 Grand Prix that I painted black with some Dupli-Color vinyl and fabric spray paint. It took a LOT to completely cover and it left the fabric feeling unnaturally rough. It was either that though or the horrid mis-matched seats that were in the car when I got it that were all ripped up, I chose to go this route as I can't afford to have them redone yet the way I want.
They have been in the Cutlass now for about a month and I actually am very happy with them. After about a week of everyday use, most of the fabric went back to feeling normal. I have never had any paint rub off or stain my clothes, and today I even drove it with wet white swim shorts and no paint rubbed off on them. The paint does fade though with regular use, but I can deal with that for now until I can get them redone.
My interior looks a million times better with the black painted seats then it ever did with the nasty ones that were in it. I have never had anyone say anything bad about them, only comments and most people don't believe that I spray painted them as well.
EDIT...
Here you can see the back seat, one part painted black, the other original color