AMD 3-WAY SLI motherboard advice

Hi
first of all i want to apologize for opening a secund thread about the same problem.
the this is, i have a crosshair iii formula and two hd6870, but now i want to go to nvidia. i was thinking bout gtx470 or gtx480 because they can do 3way sli. for now that would be stupid but i would have an opened door for future upgrades. well,
*what board should i buy? The only one i found with DDR3 and SLI is M4N98TD EVO.
*should i keep my crosshair and try the SLI hack? (afraid of that without proper guidance)

thanks in advance

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humm and what if a bought a gtx480 or gtx580 (and switch psu) it would be able to run 3d sorround 5760*1080 and 3d vision engine without lagg?

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