> I'll take a look at #3, but I'm not quite familiar with the Py3k changes 

Don't worry too much -- for the most part, Py3k is just a matter of cleanup.  For reasonable code, there usually isn't much difference between

    class Old: ...

and 

    class New(object): ...

But this means that when there is a difference, it is a pain to debug.  So just stick with the version that will continue to be available (inheriting from object), and backwards-compatibility will take care of itself.