Thinking about this currently. I guess the best way to come up with an old fashioned split-screen would be to use the canvas object. Has anyone used it successfully for that purpose yet?
I haven't really looked deeply into that issue, just been blocking out a quick prototype the last couple of days, but I'd need a strong multiplayer component for it to work.
So my current idea is that I'd need to draw the whole game and then use canvas to split up the screen horizontally or vertically. Out of my head, I don't think there's a way to define exactly what portion of the game the canvas object should display and I guess scrolling could definitely become an issue.
Just wanted to throw this out there, maybe someone here has come up with a successful multiplayer implementation already and / or just wants to help brainstorm a bit