I think the top bar is still useful. It holds the indicators, system monitors, clock, and other goodies in a small, sane, always-visible way.
I'd no sooner remove it than I would remove the dashboard readouts in my car.
Of course, you only need one side of the bar to do that, which is why maximized things work really well on the other.
Have to repeat myself here, though: I DO NOT think a menu toggler is a great, or even good, idea. This is because there isn't a single good reason to hide the menus, at all, ever. Just keep them displayed next to the title, always.
--G