With FW drives, the first computer to see the drive takes it. For shared storage, there's basically two options:
1) A server style network share solution (NAS)
2) A SAN, where the storage is connected direct to all machines, but there's some special arbitration software to stop clashes.
SAN's are expensive, but if you need one, then you need one. Here's what I'm using: http://www.kenstone.net/fcp_homepage/metasan_nattress.html It's not cheap, but it's very good and very fast. I'm guessing if you don't need the uncompressed HD speed, a NAS might be appropriate for you, or just file sharing over gigE.
Thanks for the info. It looks like for now I'll be stuck turning the G Raid off, doing the one plug in, one plug out dance, and calling it good. But tell me about this Meta Lan.
MetaLan is like a SAN over Ethernet, where your shared storage has a fast connection to one computer and a faster than normal GigE connection to the others. It's cheaper than a SAN, but not as fast. The demo is free, so it's worth looking at though to see if it's faster / easier for you.
As for better than fibre - there's 4Gb fibre becoming more and more common. There's also 10GigE. We'll have to see what happens.