Ask and you shall recieve! (Flip Top Gas cap Adapter)
I made this to have about a 32th between the body and the back of the base of the cap. However there is no reason you couldnt place a standard flat washer between the body and the spacer to give a tad more clearance. You may not want to use your original screws at that point though. Ill take it off and get some more pics of it tonight. Ill try to show the fit a little more in depth.