anybody ever use spray on bedliner?

I don't think that they would be paintable. As blk00rt stated, many of the commercial types can be tinted. What color are you wanting it to be?

I priced a commercial application last week for my Duster, a product called "Quik liner". Just to do the trunk area inside, underneath the car from the rear wheel well back and the front inner fenders - quote was $399 if I bring the car to them (it is presently on a rotisserie). I really liked the product much better than the over the counter products available as it stays somewhat pliable and would be a thicker layer. I think they can look real good myself, definately work to seal up any potential leaks - there is a lot of caulk and seam sealer on our cars from the factory, and, they can cover up a lot of amateur welding in my case! I am more interested in the practical aspects of having the car sealed tight as I don't (or won't) have much on it that is numbers matching.

Good luck, let us know what you decide.
C