ermm this is possible on amiga also.
shapeshifter is an example!
anyway i used to have this just for fun .. 1 monitor as wb and rest for ibrowse/amirc / yam etc , and a third monitor for games (using the tooltypes in my monitors dir..)
playing babeanoid on 1 screen , seeing what people write on irc in another and the third one has the yam open..sadly i cant multitask in stuff like babeanoid but it does work

anyway 2 monitors is supported in SS with the overlap funcion..
check it...
enjoy