I don't think you know what the term "legacy" means...

The correct word you're looking for is "obsolete". Legacy means something completely different.

Could be useful for custom CUDA programs that use a lot of memory, or maybe hacking so it runs the Quadro drivers (and thus save several thousand dollars on a pro card with the same amount of ram).

You are aware that the GTX260 uses the exact same 55nm die shrink of the original g200 as the GTX285.

http://en.expreview.com/2008/12/05/first-look-of-55nm-geforce-gtx260.html#more-1550

So exactly how would the GTX260 be a legacy part? Though I agree you would be daft to spend the kind of money they are asking for nothing more than an unnecessary memory upgrade.

Why do I see all of these "custom" GTX 260 popping up out of nowhere?

The GTX 260 is a dead card. It became legacy equipment the moment that the GTX 285 hit the markets.

Why bother creating non-reference designs of an old card? And why bother charging MORE for these silly legacy cards when you can pick up a GTX 285 for less money and get more performance?

I suppose if someone absolutely had a fetish with the "GTX 260" name they might want one...

Hrm I wonder how two or three of these would fair in SLI? Just a curiosity since SLI has to have memory replicated between the cards. May make zero difference in current games but it is curious as I cant think of any other use that could possibly touch that much video ram. Well besides professional graphics applications which nobody in there right mind will buy this for since its not optimized like the quadro series is for professional graphics.

I will have to keep my eyes peeled at Toms Harware for a test of this card. I am curious as to how this would stack up against my XFX GTX 285 (1Gb) card

cant help but thinking this is much more memory than a 260 could possibly need and use!!