Cool. Looking over it. I am working on something similar. I am using ctypes though thats not a big issue.
About license : would you consider some other license than GPL? Since its a library that people will link to, might be better to license it under LGPL or BSD or something though since you are the author, thats upto you.
(I will be using Apache2 when I release it).
I was a bit puzzled deciding GPL<->LGPL and temporarily chose GPL but I think I'll go LGPL with the next snapshot (I hope to have it out at the end of this week or at the beginning of the next week).
About ctype: it is propably better for most things as much of my code looks heavily redundant (all these classes representing various things, having nothing but constructors and destructors and lots of glue code). As I don't mind programming C, I didn't care much about this. Some things need to be native, however, like CalResource<->Numeric.array integration - this way it is possible to implement resource objects as Numeric.array descendants thus eliminating many bulk data copies into and from resource objects (planned but not implemented yet).