Disclaimer: I'm not one of the "hard hitters" so consider the source... On the other hand, I've been around a bit and I think I know what the machines are doing.
Multiclip and HDV sounds like a recipe for disaster to me. "Native" HDV wants a lot of horsepower, so does Multiclip. But if you have access to a fast hard drive array, I'm betting you could cut a ProRes 422 multiclip pretty easily. If you have problems, they'll probably be disk speed-related since ProRes needs 3-4 times the bandwidth for playback.
I did something similar to what you propose a few months back, but I did in on a 2.5GHz G5 dualie and a 4-drive SATA RAID 0. Clearly, I lived to tell the tale... ;-)