Not in maemo. Maemo has alarmd which is better than at or cron for one simple reason: it is hardware supported. It works when your phone is switched off. And it has powerful recurrence support.
Unfortunately there is only some doxygen documentation, several examples in the wiki, without recurrence support and that's all. We didn't manage to find any application, which uses it, but now you can see how it is implemented in ET-Prolog.

Alarmd does not support exclusions, but you can model them with boolean logic. I also use temporal logic for defining start and and of periods.

By the way. I couldn't find how to obtain shepherd and see how it is implemented. Am I right, that this topic and wiki page is everything available?