Hi Mickey,
I was also looking for a clean way to organize my daily ipkg builds... Are you keeping some kind of magic script hidden somewhere, or do you just organize by hand?
For distribution, your suggestion seems good. As far as I understand, this consists in keeping only the *_simpad.ipk, plus some packages for which I have to use a newer version than the one in OZ3.5.3 (such as opie-wellenreiter), and use OZ3.5.3 for the rest.
(PS: Yes, I am considering to candidate as a maintainer for OpenSIMpad - if only I could manage to get the keys working again in the latest builds...)