I live in Emeryville, so I'd be interested.
Now then, for a 6 way LAN connection, we'll need a 6-way LAN hub, at least 6 RJ45 network cables, and 6 PS2s with network adapters along with 6 TVs and probably enough space for 6 wheel/pedal setups.
It would be a good idea to contact Famine about a good way of running the event too, since he's done it several times in the UK. Search for UKGTPIV for his thread on the last one.
You need to have a good balance of cars & drivers and tracks, since if everyone insists on racing a stage 4 turbo'd Minolta at the Test course, I'm not interested!
There needs to be a way to keep the faster drivers competetive without making slower drivers spend a lot of time sitting out, especially if there's more than 6 people.
Hope this helps, will keep checking back here to see how things are progressing.