Coincidentally, just the other day I was researching some articles about doing this.
I’ve not attempted it yet, but these (along with the MCXRedirector one mentioned in the comment above – that looks useful too) should give you some pointers.
What I’m thinking of is the way Macs are used in some schools, where the user profile is the same on all computers and picked up from the server.
Or the NetBoot option?: http://www.apple.com/server/macosx/features/client-management.html