anybody ever use spray on bedliner?

I used Dupli Color's version of that stuff on the bed of my 1985 Ram. Dupli Color's is able to be thinned with Acetone, which I did, and sprayed it through with an old, cheap gun I had laying around. It went on nice and was very durable, I put 3 coats on to build it up. As far as being paintable, try calling the manufacturer, ther should be a number on the can or maybe the place you bought it might have a number. Good luck.