You already know I don't have much experience with Linux on the desktop, so can't offer much advice. I do know that there are a few companies selling multi-monitor setups, so that might be useful to you. Here are links to those:
http://digitaltigers.com/zenview.shtml
http://www.monitoroutlet.com/multimonitor_nec_main.html
I'm not sure if any of those would be better than having three individual monitors, though.
By the way, that Compiz Fusion program looks quite awesome. I just watched a YouTube video on it and it seems to have some great functionality.
