My experiments back during the dailies of 7 when I wanted to know how this kind of look would be handled with the new Phys Mat suggests using the Absorption in the Clearcoat (basically, an extra coating of some sort of oil-like material on top of the base glass). Just remember that the clear coat colors everything beneath it, so don't make the colors too strong (else it will start to look like colored glass :) ).
I thought this was shown somewhere but I can't find it, so here's the scene re-opened and screengrabbed, I think with some playing it would give the desired kind of effect.