tarren could you provide us with some pics of this? i just want to see it! lol i have never heard of anything like this. but if it were safe the 240 guys would be useing it, they allways want the 5 lugs, instead they do the 300zx conversion
they do make them, but not a good idea. If nothing else, and ignoring the shearing issues put onto the adaptors, they screw up the offset of the wheel. If you must have them, take the rotor to a machinist and have him punch out the 4 lugs and drill them for 5 lugs. Make sure they are good though, you want it exactly in the center, and you want it balanced.
I have talked to alot of people who have used them with no problems.(mainly on 79-85 rx7's which have a 4x110, extremely un common bolt pattern) I have never actually heard of any recorded issues with safety, but that doesnt truly mean theyre safe.