I've got pereference about using Gnome with Xmonad, and there's alse blogs about using Xmonad in Unity-2d.
Persionaly, I really like the way Xmonad manages windows. Also, the way Compiz places workspaces is great, I was travalling among a 4x4 wall of workspaces when I was using Unity. So I really want there was a way to combine them togather. But it's hard to make my own idea as I'm still a green hand.
Is there any implements about all those so far?
Short answer no.
Unity just a compiz plugin. Compiz is a compositing manager and Window Manager. What you want is for Xmond to support neat effects like Compiz does. To do so someone would have to write haskell bindings so that xmonad too handle compositing effects. Needless to say this is not trivial.
It would be far simpler to write a Compiz plugin to handle window tiling effects..