If you are going to have a new shell, then why not design it on top of KDE4 Plasma? The Plasma desktop is extremely flexible. It supports scalable vector graphics (nice thing to have when scaling up the desktop as you can do with XP), OpenGL graphics (for a Vista style ReactOS desktop) and everything is a widget (nice for a 'skinned' XP interface and Vista gadgets). The KDE4 Window manager is also OpenGL, so you can create the Vista 'scroll through windows' effects. KDE4 ofcourse also allows 2D rendering for the older interfaces (XP and earlyer).
It would be nice to see the option, just like in XP and Vista, that allows you to have a classic-, XP- or Vista desktop.
I have no clue to wether KDE4 can even be intergatable into ReactOS though. So please enlighten me
What are your thoughts on this?