General Question

Yes you can, a few ways to skin that cat.

1) Use OSX Server, use network accounts with network home directories. Everything is accessed over the network, exactly identical across systems. Drawback: nothing stored local which means if you're off network, no accounts.

2) Use OSX Server and Portable Home Directories (called Mobile home directories in some of the docs). This creates a local copy of the Home and preferences that you can set to sycn on login/logout and while connected. When your not connected, you still have access and it will re-sync when you reconnect. (this is what I do). Drawbacks: sync issues - remember to login/logout on your portable before going offline to ensure you have a recent snapshot, try to only login/logout to one system at a time for a particular user so it doesn't get confused on which change to keep.

3) Use dropbox and use symlinks from the dropbox folder to the folders or files you want to keep synced. Works well. Drawbacks: limited size/space, sync time (although it can detect if your on a LAN and speed up the sync), security problems (Dropbox's security model is not so good - no user managed encryption key). Other services like SpikerOak are similar without the security issue, but I haven't tried it yet.

Good luck.