As far as RE5's development is concerned, don't forget that RE4 was completely scrapped I believe it was three times. It was going to be a game where your enemy was your growing dementia or something, one where you were fighting unseen forces, another with just plain zombies, and lastly the not-zombie zombie people.
It's hard to say what could happen with a game that's been essentially non-existent for 2 years. I can't imagine it would cost more than $1-2 million to make it for the Wii if Capcom decided to. All it would need to sell is 250k (not counting sales poached from the other consoles) to justify that price. They'd have to do it in a different engine to be sure, but the levels, story, characters and such would all be finished.
Something else to consider is Japan. I don't know how big the RE fanbase in Japan is at this point but it's becoming clear that any game a dev wants to sell well in Japan is going to have to be on the Wii. If Capcom expects RE5 to do well in Japan they'll have to pay the price to move it to the Wii which means they may as well do it here also.
