So, can you make your Hildon desktop transparent so that you can see a standard X wallpaper that is behind Hildon Desktop?

Answer: Kinda-Sorta. The problem is that all the Hildon home applets are the same window as the Hildon background, so everything becomes transparent.

Here is my OS2008 desktop, with a plain black background, then set transparent. The "Debian Tree" image is from a previous run of LXDE. LXDE paints its background directly onto the X server (like most "normal" desktop environments), and the xomap-xserver just leaves the last image as the background...

Anyway, this is a proof of concept that yes, if you were to use a wallpaper-changing utility, you could have changing wallpapers on your OS2008 desktop... The cost is that everything on your desktop looks ghostly and transparent.

The best solution would be to hack the hildon desktop to have a completely transparent background (while keeping the applets properly opaque). This transset technique is a bit of a kludge.