You have probably guessed what this is already from the thread title, but I am currently in the process of making a Windows Vista Template/Theme/Skin, to be used for blogs. I am initially going to make it for Wordpress, but I will alter the code accordingly for it to work with other blogging systems (suggestions please). I have designed the template so that I can put different backgrounds on it, with it still showing the transparencies (I haven't just sliced the screenshot, as that would mean the user would be stuck with the green grass).
I made the template in photoshop, from this screenshot:
Here are my preview images (different backgrounds):
Upon its final release, it will be 100% free.
Let me know what you think.
NOTE: It IS NOT 100% perfect, or accurate to the appearance in the Vista Beta 1 screenshots, but is designed to be as close a representation as possible.