Let's forget about trying to find a brand that works. It doesn't exist. Testing at this point is a waste... all the testing that can be done has been done. There is something wrong with the power circuitry in the card and how it affects the analog signals originating in the card. Besides pure digital signal, the only other solution has been to remove the additional 4 pin power connector. At this point there are only a few things we can do:
1) RMA or hold off buying 59xx and wait for NVidia to give us official information... something that is looking less likely every day, probably because they realize the enormity of their blunder.
2) Buy the 5900 SE cards coming out this fall, with freshly made GPUs from IBM and hopefully better board circuitry.
3) If 5900 SE is still flickery, wait for NV40 in the spring to fix this. (I'm not that patient.)
4) Switch to ATI and deal with their continued buggy drivers but SOLID picture.
Personally, I am going for option 2, followed by option 4.