Rolly-
I am not aware of any quality 6x50 illuminated scopes out there. It may take a little luck, but you can find 7x50 and 8x50 with very good illumination, and GPO currently offers a 7.5x50. I believe there are still a few Meopta 7x R2s floating around. And, of course, there the SB 8x56, but you specified 50mm.
I have a couple Zeiss Diatal Classic 7x50 scopes and love them. I also have a Swarovski PF 8x50 with BE-1 illumination and a 4-N reticle that is superb. But those don't come along every day. If you look up forum member artur, he may be able to hook you up with a used one as he spends much of his time in Europe.