Lee,
just a short answer (i am currently in the alps skiing).
it looks to me that we have two different kinds of problems to solve:
a) how to dispatch certain messages to different kind of consumers (e.g. packages, or acs-objects) and
b) how to address certain services via email. This is a typical remoting problem,
it makes certainly sense to think about the more general problem. In the best of all possible worlds, i would like to see a dispatch mechanim, that is able to handle dispatch via URLs (request processor), dispatch via SOAP, and dispatch via email (and maybe different interfaces). all these dispatch mechanisms require similar services, like permission management or package resolving, etc...
I can't offer a detailed design, but i think its worth to think more on the architetural level, which offers various patterns for such kind of problems. we will try to prepare something in this direction for our workshop...