To create your own wallpaper.
Tap on the publisher and then the (title or titles) you want to build your wallpaper from then tap on "Next"
Select up to 4 images to build your wallpaper (notice the highlighted background on the selected images) from tap on "Create Wallpaper" and in a few seconds you will see the "Success" dialogue. If you are having any problems with this functionality please let me know I have tested on the "MyTouch" and the "Nexus One".
And here is the final wall paper we just created:
Here are a few of my favorites.