Pardon my enthusiasm for the DBus idea.  What I meant by "extended goal" is that I would first design, implement (a subset of), and test the API.  Then, time permitting, I would add the DBus functionality that would bring the system to a reasonably usable state.

As far as Guile, Swig, etc.  I believe that DBus gives us most of that since it is inter process communication and it doesn't really matter what is on the other end (say, a Python program or script.)  Regardless, I believe that dealing with language bindings and linkings (however we decide to manage them) would be an extension to this summers project, otherwise it would be easy to bite off more than I could chew.  For now I will leave that up to the users of the API.

I am very intrigued by the concept of using XForms.  On one hand they seem like a potentially elegant solution.  On the other hand, whether or not they could or should be used this way, they certainly are not usually used this way.  Given the moderate information I was able to dig up about them I'm not sure that XForms would be the best choice for a student project, which should be on fairly solid ground in terms of probability of success.

Does anyone who has experience with XForms (or discussed it) have any advice about the feasibility of using them for a relatively short project?

Thanks for all the helpful comments,
   Soren Berg