i think your best bet if you want to get a mac pro is to run windows on it till cs3 ships.
it sounds like you have the windows software versions already so load them up for he next few weeks, then once you get CS3, id start over on the mac side.
i dont see how a 3 drive raid is going to get you any reliable 10bit HD though.
i know blackmagic tested that config and said that 8 bit should be fine for capture and playback.
who is that masked man…
https://www.exposedideas.com/