After a quick Fry's run last night, I sat down and built a Cat-5 VGA cable, per your instructions, using shielded Cat5 cable and a shielded coupler. Overall, the image quality was very nice, certainly much better than the replacement VGA cable I mistakenly bought last week. (ghosting like you wouldn't believe)
However, I did notice a small amount of noise in the image, when compared to the 3' cable I usually run between my HTPC and my DLP projector. Did you do any A/B tests using a standard cable and notice any differences? (I don't think I would have noticed any difference if I was using a tube based display)
Also, did you jumper the shield wire to the metal frame of the connectors? (haven't tried this yet) The shielded cable I picked up (the only one I could find on the shelf
) was only rated for 100mhz, as opposed to the 350mhz cable I usually use, not that this should make a huge difference here, but thought I'd ask anyway.
This was more of an experiment for me at the moment, as my HTPC and projector are right next to each other. But a cable of this type will be very useful when I add an HDTV set-top box to the main equipment rack on the other side of the room in a few months. Now I've got to open up one of the wall jacks this week and see what kind of Cat5 the contractors put in last year.