I've seen decks use the NO Prog package as part of a sideboard strategy. 1 Progentitus, and 3-4 Natural Order can be brought in against matchups that warrant it. It's a nice surprise tactic, and a lot of control decks will likely be siding out their counterspells against Rock in games 2/3. You can easily enable it on turn 3 via Deathrite shaman, and either sac the shaman or a Dryad Arbor you've fetched up. I don't think I'd really want to play it maindeck though.
Also, you don't have to limit yourself to just Progenitus. There are numerous fat green creatures that'd be worth NO'ing into. Terastodon, Worldspine Wurm, etc.