A couple of months ago, after an update, TaskSpace stopped worked properly with ConnectedText's floating windows, and so I stopped using it. But just a few days ago I got frustrated again with not being able to organise my floating windows across 3 monitors and contacted the TaskSpace developer about it. I should have done that in the first place, as he sorted my issue within a matter of hours and I'm a happy bunny again. TS seems to have come a long way since the OP, so here is a mini review/overview of things that have changed:
Dragging windows into it doesn't capture them...
There are now a few very handy shortcuts, including "move current window to last active TaskSpace" (CTRL+SHIFT+M), so there is no need to drag and drop even (especially useful if the TaskSpace window is on another monitor).
EDIT: bah, it doesn't group then in the sense that they mini/maximize together.
TS can do that now. Another related option that has been added is "Always on top" or "Normal".
Looks like it only works on 32 bit win 7 
There is now a Win7 64 -bit version as well.
Maybe that's the reason it's free 
It has moved to a freemium model.
when moved between different monitors (with different resolutions and sizes), the docked windows can get a bit messed up, so need manual rearranging.
That's been resolved.
One needs to be pretty careful during installation though not to install all the adware stuff...
Looks like that's no longer there, now that it has gone freemium.
There are a few minor issues that the developer is still looking into for me, but overall this is coming together nicely. But I've only been using it with CT, so YMMV. I recommend getting in touch with the developer if you run into any problems, as he's very responsive.