This seems spaghetti-ish (and not very MVC).

Its no different than the alternative you propose. Here are some articles which might help you organize better (in terms of MVC):
A short introduction to GUI programming with the MVC ...
http://wiki.wxpython.org/index.cgi/ModelViewController
http://mail.python.org/pipermail/python-list/2004-April/216826.html
http://lists.wxwidgets.org/archive/wx-users/msg12396.html