There is speculation there may be one, but I don't think it has been confirmed or denied really yet. Just have to wait till we get closer to the release.
Reggie said in the interview that it wouldn't make sense to start bundling Wii Fit with Wii when there are still shortages in Wii, however after the demand goes down it could happen.
I'm sure that when WiiFit is released, it will not be bundled with the Wii. However, as time progresses, there is a chance that it could be [as mentioned above]. Just hoping the game lives up to it's expectations.