I think ThemeMaker 1.1 produces themes which are moderately compatible with OS2008, but it uses an incomplete template file. Many (perhaps most) graphics have to be edited individually, rather than within the template image. The latest version is here:
https://garage.maemo.org/projects/thememaker/

Old versions of LCARS were made with ThemeMaker, but for the OS2008 themes we used Nokia's hildon-theme-tools software instead. This tutorial is a good place to start:
http://live.gnome.org/Hildon/ThemeHowTo

We also added some additional elements, and put up a page describing how to modify and rebuild our themes:
http://synthesize.us/LCARS_PADD/HOWT..._hildon_themes

Good luck