Have you ever tried running a 1920x1200 monitor with a MB? If not you should run it with your supposed G5 iBook (see his other posts). Or you cold run it on your friends Mac Pro 3.0GHz with 16GB RAM.
My advice memoteran, the GMA 950 isnt that bad of a card but you might see some lag or choppiness when you run a monitor at the cards max capacity.
I would think it would run fine, but personally have never tried it. I woud carry it into a local Apple store and hook it up one of the cinema displays that supports that resolution.
My wife's MB runs fine through DVI on my 24 inch dell at 1920x1200.. Unless you are a heavy 3d gamer or are using 3d apps, go for it. The extra workspace is great.
the top res for the macbook does produce stagger when watching dvd's on an external screen. also it doesnt fill the whole screen but as a box within it. this connecting to 26" lcd LG via hdmi will try the 43" pioneer plasma when i get home
i have one connected to a 23" and it works but sometimes slows down, it was enough of a problem that i'm selling the macbook and getting a pro. as long as you're not doing heavy multitasking you're fine, but if you are i say no.