Alright,
I just uploaded version 0.14.0 to extras-devel.
Besides fixing some minor issues this version adds:
- support for using custom images for drawing the digits,
- support for animated gifs,
- and a working twelve hour mode for the binary clock.

The "custom images" feature should work with any of the present "stock" clocks that write digits as text.
The "animated gifs" feature currently only works well with the "Decimal Clock".
For the animated gifs feature to work it is important that:
- the animated gifs do not loop,
- and the animation time is shorter than one second.
Overall the new functionality is still pretty experimental.
I'd appreciate if you report any bugs you find either here, or even better in the projects bugtracker.
The settings user interface is also not 100% correctly implemented yet: it displays "." and ".." as entries.
I'll fix this but I finally wanted to get this version out in the wild so that you can leave feedback about the new features.


With respect to the "main loop":
Actually, there is no real main loop in the code in the sense that you would see some "infinite loop" that sleeps for some time and keeps triggering the updates.
Instead I used gobject.timeout_add to add a timer which triggers the updates in intervals of one second.
If the show seconds option is false then the logic checks whether the value for minutes has changed to determine whether an update is needed.
This whole logic is in "/usr/lib/hildon-desktop/advanced-clock-plugin.py".

In the current code for handling animated gifs I also used gobject.timeout_add to "install" a timer which triggers the updates for the animations.
Actually, this could also be a possibility to get an animation done.
Though, you have to keep in mind that the animation should not loop (i.e., eventually finishes) and it does not run longer than one second.
Else, for those who really want a fast refresh for having animations all the time could change the refresh delay in the gobject.timeout_add calls in "/usr/lib/hildon-desktop/advanced-clock-plugin.py".