Honestly, I've always wanted a window-manager that mimicked Visual Studio's pin/dock slide-outs. That is, you can dock any task to any edge of the screen, and each edge can be sub-divided into panes. Each pane has multiple tabs, and each pane can be set to auto-hide or can be "pinned" to always-visible, which causes everything else to resize.

It's a rather complicated approach, but I've never found any better multi-tool layout, since it's enormously Fitt's-law-friendly while allowing me to both hide everything or bring in oodles of tool panes quickly and easily as needed.