I haven't been around much. I don't have internet access at home right now, so I don't know what news there has been for the theme engine.
So I had what I hope is an epiphany. John you said you found a png lib to use, and that we could use alpha on buttons. Could those buttons be displayed over an area of the background that is transparent? If so, could you make the entire backgound transparent, and create a "button" that is the actual form and displays behind all other buttons. Alpha to the desktop?
I also have another cool idea for layering images. I'll make a screenshot when I get home, and upload it next time I get online. It'll be easier to explain with a picture.
I hope this idea will work.