[Rolphus]

This is quite an interesting idea, although it sounds like it may require some replumbing of the workspace system. If a cached image representing each tab was stored in the workspace itself, then the enormous (almost exponential, it feels) bogging down of the browser when loading up increasingly big workspaces could be avoided until the tab itself was clicked on. It would mean a minimal delay for the user when switching to a new tab for the first time, but for my usage model this is a minimal problem.

To take it one step further, the system could introduce priorities - background tabs are loaded at a lower CPU and network priority level than foreground ones, so that huge workspaces would eventually get loaded (but perhaps not rendered) without the user clicking on the tab, but this wouldn't get in the way of responsiveness of the foreground tab.

Of course, I'm no Webkit/Cocoa developer (.net for me, unfortunately), so I have no real idea how possible this is.