From all the research I've done on Pokegods and Glitch City and stuff I'd have to say this:
Pokegods do exist but they aren't actually gods. They are glitches like Missingno that can only be gotten via Gameshark. I know they are real because I tried one of the codes on a Japanese Red ROM and caught one with a jumble of letters as a name, a Rhyhorn's sprite, and no attacks, I don't remember what people nicknamed it though... People gave them names of prototype Gold/Silver Pokemon (like Pikablu which turned out to be Marril), Pokemon that were on the show but not in the games (mainly Togepi, I think one was Ho-Oh's Japnese name, which seems to have slipped my mind at the moment, but don't quote me on that), and completly made up Pokemon (like Venatoise and some evolved form of Nidoking/queen)