I finally purchased Window Blinds 5 yesterday. At $19.95 it is one incredible app, and I have to say that I like what I've seen so far. The most awesome feature will obviously be per pixel αlpha blending. Here's a screenshot of my desktop with VistaXP v3 Visual Style by KoL, of StudioTwentyEight.

Though I have to say that the most impressive thing about WB5 that amazed me is that it doesn't need to any dedicated process in order to run, it runs as a native Windows XP extension there's no exe that loads at startup nor there's a background service. I used Process Explorer by Mark Russinovich but there's not even a handle that I could find to wbload.exe or wblind.dll or tray.dll. Now that's neat!