I don't know how much it might cost yet, but... I am planning on measuring up and cad modeling the stock dust caps, adding some room and fins for cooling, and getting them machined out of aluminum. Now, these won't be cheap like Morimoto's rubber extensions that require you cut apart your stock originals and end up insulating the bulbs. These that I'd get machined would be setup to accommodate something to help transmit heat from an led bulb's heatsink out to the dust cap, something like a wad of aluminum wool. My guess is they would cost $100 a pair. If I get something successful setup, would anyone else want some?