If you grab an Intel Lynnfield processor and a matching P55 motherboard when they come out (likely September), you may be able to run GeForce graphics cards in tandem without issue. That's because Nvidia has licensed its SLI technology to Asus, eVGA, Gigabyte, Intel, and MSI for use in P55 mobos specifically.
Nvidia explains, "Customers who purchase a validated P55-based motherboard and Core i7 or Core i5 processor when available can equip their PCs with any combination of NVIDIA® GeForce® GPUs, including Quad SLI."
We saw the same thing happen last year with X58 mobos for Bloomfield-based Core i7 CPUs. Last quarter, both Gigabyte and MSI also decided to add SLI capabilities to their entire X58 product lines. Adding SLI compatibility involves paying Nvidia to certify a board, then adding an approval key, or cookie, in the BIOS. GeForce drivers check for that key before enabling multi-GPU mode.
Incidentally, this announcement echoes the Core i7 and Core i5 brand names for Lynnfield processors. We're now expecting Intel to release a 2.66GHz Core i5-750 with four cores and four threads, plus a 2.93GHz Core i7-870 with four cores and eight threads.