Gigawire is supposed to be a Firewire 2, which Rendezvous is very much something different. It is reasonable to assume that "Gigawire" actually Firewire 2 because A: We know a firewire 2 is coming (Firewire is behind USB2 right now, and we cant be having that), and B: the fact that they share "wire" in their name.
Furthermore, If Gigawire were Rendezvous we would have heard by now, probably.
Gigawire = physical medium to connect devices together
Rendezvous = software used to request services on a network without configuration (ie. Who here is running iChat, Who here is sharing their iTunes library?)
i read about a day or two ago that somebody had already made an announcement about having gigawire external hard drives available soon (i'm tired and too lazy to spend an hour searching for who it was). but rendevouz has nothing to do with hardware (other than providing a medium of exchange between networked devices).