Comment: A few notes (Score 1) on 2010.05.25 6:49
I'm glad you have the enthusiasm to work on this project. As you know (and some other readers here may), I've also proposed a CTypes for Perl project to the TPF two or three times, but it wasn't accepted, so I'm glad it was accepted as part of GSoC.
I'd like to note that when I requested help with some ctypes (in Python) problems on #python on Freenode, some of the people there told me that they now prefer to use Cython over ctypes and that "it also has a strict subset so that a cython module can be used directly in Python, rather than compiled" (but "idea how good that is though.") so it may be worth to investigate. Cython is not a core Python module though, which has been the case for ctypes for a few years now.
Otherwise, note that your first interface is procedural rather than functional (see Functional programming on the wikipedia, which is not the opposite of Object Oriented programming). The interface looks fine, but I think we may eventually overgrow the pack/unpack like notation because ctypes and the C programming language supports quite a bit more than what unpack gives. Also see the Data-ParseBinary CPAN module, which also has origins in the Python "construct" module, and which is far superior to pack/unpack.
I agree with the other people here that we should call it "ctypes" or something and not "ptypes". I tried to log-in into twitter and follow your tweets, but it said that "Twitter is over capacity." and wouldn't let me. I'm not visiting Twitter a lot often. In any case, I'm subscribed to the use.perl.org master Perl feed, and you should see about getting it syndicated on the various Perl planets.
Good luck with perlifying ctypes.