Quite some time ago there was a question concerning maemo-mapper and hybrid images. Looks like there is no major obstacle displaying them - only some more hacking and having multiple mapping directories as precondition.

The following patch should be applied after armin's patches. With one directory for google earth and the other with uri:
you get the effects of the screenshot, when switching directories.

Currently it's only proof of concept and not really useful - more work has to be done.