MDI-like widget?

[Timo Sirainen <tss iki fi>]

I don't mean the traditional "windows inside windows" MDI, but rather that
kind of what MS Visual Studio (don't know what other programs have it)
partly uses. Some of it's windows dock at the borders of the real window,
they can be moved to different border or above/below other docked windows or
removed completely as a separate real window, but they never float around
freely and other windows don't overlap them.

So I was thinking some container widget that could do this automatically. I
could add widgets to left/right/up/down and it could be moved around or
separated as new window, and the new window could be docked back (like
tearoff menus). These docked border windows would be mostly for some utility
windows, like file browsers and such. There wouldn't be that many of them. 

In the middle there would be the working area. I'm not sure how it would
behave, maybe have some windows that could be split horizontally (and
vertically) and they also could be moved around but not necessarily behind
border windows ..

The windows themselves could have some simple title bar that could be used
to drag the window. Window resizing should of course also work, but while
growing one window others would shrink.

GtkTable works pretty much the same as this, except I don't know if it's
possible to move and resize widgets in it, or to add/remove rows/columns in
the middle of the table.

So the questions: Has anyone done anything like this yet? Does anyone want
this kind of widget? Is anyone willing to code it? ;) I might try it, but it
would take a long time and probably would just end up as ugly and buggy code.