I've been toying with this idea myself. What I was thinking, is since the inside reflector is of no use with installing a projector housing. I was thinking about removing it and making a flat base to mount a 3" and a 2" projector or mount a 7" and 2" and remake the inner ring to fit the new lights or maybe just alter it.
Here's the 7" i've been looking at.
The only thing I haven't done was to measure the holes in the core support to see how much room there is.
81 AMC SX/4 "Go Mango Orange", 99 Vx "Astral silver",01 Vx "Proton Yellow", 02 H1 "Competition Yellow" and "lil pigglet" 05 Zuma "Team Yamaha Blue/White"