NAND is a form of flash memory, which is unrelated (to some extent) to RAM. It's much more comparable to the chips you find inside SD cards and such. Anyway, that out of the way, I believe Samsung or Fujitsu showed off a laptop during CeBIT that had a 32GB NAND hard drive.
But NAND is very expensive. Don't expect it to reach market-friendly prices in the next few years.