On a positive note, I can report that UltraMon v3 **finally** went into a useable beta on Jan 11th. After running it for a month, I can say that most of the crash issues have been fixed.
$40- for a new user license. Upgrades for previous users are 1/2 price.
I also recently tripped acress this nifty-looking utility:
http://www.zoneos.com/zonescreen.htmZS has the upside of being free for personal use but I've not had the chance to test it against UltraMon, the various Matrox dongles, and plain old VNC hookups.
As far as secondary monitors go, this is another area where JR could differentiate MC from the rest of the world. Supporting secondary info monitors regardless of connection (USB, video card direct, WiFi, MID, etc, etc) and capability (touchscreen or not, remote mouse or not, etc) isn't something we see elsewhere.
I think that we're already there with the concept of zones. Now for some point and click setups to shift info views to secondary displays and reserve the primary display for video or visualizations.