Thank you for this comment. I spent years thinking emacs was cool, but didn't quite get the push toward using emacs for everything but the kitchen sink until now. Time to take another look at it, I suppose.
He could still run Xmonad and have a workspace for a browser, only switching to it when he wants to check something. Running a proper window manager will not interfere with how many things he wants to run in Emacs.
I've run Xmonad bare on a dual core 1 GHz machine with 512 MB RAM and it ran great. The processes he runs are going to vastly outweigh Xmonad in terms of resource usage. This is one of the worst non-solutions I've seen to this, when he could've had the same setup without any of the hassle.
Most tabbing window managers also provide a pretty good scripting interface, but the programs you run inside them tend to be more opaque. If you run the ncurses RSS reader 'newsbeuter' in a window, your WM scripts can't easily interact with a running instance, short of screenscraping its output and sending it raw keystrokes as input, because it doesn't expose any kind of API.