Just to add - next bit of work on this is to switch theme without leaving the current page, and save selected theme to the user profile preference. I used navigation dropdown menu for this originally but as you can't script theme changes in Moodle 2 menu (unlike 1.9) it defaults to the home page every time you change theme.
I should have this sorted by the time I rollout a 2.5 version of the theme.
Regards, Gordon.