Wich Ultra-D Revision is moddable to a full Sli board?
I'm planning to get 2 7900gtx's and don't really want to buy a new mobo?

According to the experts here, they can all be modded. But later models have a layer of epoxy on them that has to be scraped off first.

I haven't done the mod myself yet, waiting for 7800gt's to get a little cheaper first

Any of them and the epoxy aint no big deal - take your time. (I used a conductive marker)