The only nForce2 board of the top of my head that supports IDE RAID is the Chaintech 7JNS Ultra Zenith ($141 @ Newegg). Kinda expensive, and I hear it's not the best overclocking board ever.
You might also want to look into getting a cheapish nForce2 board (Shuttle AN35N Ultra, Abit NF7) and buying a seperate PCI RAID card. That might be more what you are looking for.