Well technically that doesn't stop it. It would prevent the changes from being as big as an evolutionist might expect, but it wouldn't stop it altogether. I'm wondering if creationists reject macro evolution outright, or do they just reject the timescale being so large?
Fair point. I think it depends though on what creationists would accept as macro-evolution. Usually they want something like a fish growing legs and turning into a frog, which isn't going to happen in 6000 years. What creationists would consider macro-evolution takes more than 6000 years and is therefore impossible. I have no doubt that Jason78's example above will be rejected as an example of macro-evolution.
I like where you're going with this, Arch. Would they accept that if
there was enough time, then species level evolution is at least hypothetically possible.
I'll be impressed if you get any creationists here to bite, though. Good luck!