I think option #3 is the most realistic. I saw your photo of the round omega glass - I'm sure some sort of fastener could be devised to hold it slung under the original HA glass location. Even a loose piece of oversize HA glass slipped between the lamp and the dichroics (not attached) might be workable.
Originally Posted by George Nova Scotia
Option #4 is a good idea in general. You never know when the gremlins are going to hit...it is always good to have a backup. The problem is that 2nd hand units are getting harder and harder to find. Several years ago they popped up on ebay at a fairly regular clip - now they are few and far between. To make things worse, the prices of 2nd hand 500 systems seem to have been climbing quite a bit as of late.
Option #5 - It might work, but I don't want to be the one to sacrifice the dichroics in my 500h to find out