Has anyone tried this one http://www.grandtec.com/POP1280S.htm yet?

Well I bought mine from Tiger Direct for a little cheaper. Try searching CNET.com for the best deals. I have mine hooked up to the CMV 520D. I'm currently using only the S-video hook-up but I must say after the proper adjustments the picture does look excellent. Now mind you I have just started to get all the parts for my project so as of now I don't know what the finished pruduct will be. I chose the POP because It accepts multiple inputs and it is a whole heck of alot cheaper that an HTPC. Now I'm not saying that you'll get HTPC result either but I'm trying to keep my pj budget a little closer to the advertised building cost. What ever you decide good luck and happy building. I should be starting my pj here very soon. Other users have discussed this product in other forums so keep searching and reading. And then read some more!

This looks like it would be a viable alternative to the Nextvision N6.

The N6's image quality with component in is completely unacceptable.

Does that say it supports 1280x1024 @ 75 hz?

According to the spec on their website, yes it supports 1280x1024.