Mortgage Rates Could Go as Low as 4.0%?

I just read this AP article mentioning the GOP wants to add more mortgage relief to the stimulus package.
Officials said the GOP was coalescing behind a proposal designed to give banks an incentive to make loans at rates currently estimated at 4 percent to 4.5 percent. Fannie Mae and Freddie Mac, which were seized by the federal government in September, would be required to purchase the mortgages once banks have made them to consumers.

With current national rates hovering around 5.35%, this would definitely spur many homeowners to refinance. As mentioned before I am in the process of refinancing and have a lock for 4.75%.  If the rate were to go down to 4.0% I might have to refinance again.