tintable undercoating?

http://www.tcpglobal.com/CUS-KIT-TB...LIn63009CQt_dV5GvEVTjhoCLobw_wcB#.VxkHStQrIsY

Bed liner but should do the trick. I used to spray in bed liners and while wet you could also spray some of the body color over it. This was before they started tinting the bed liners.