While I agree Venonat would be awesome support for Porygon; I'm pretty sure the point of this thread would be to suggest mons to build around. You're jumping the gun to Step 2.
Venonat itself can be built around though; lots of things enjoy an (almost) equivlent spore/AgiPass.
Anyways; will post a set I have in mind after I test it some.
(01:44:11) +blarajan: stop organizing threesomes in the main chat.