Greg Hathorn, of Sam and Greg's Pizza, talked to WHNT about an idea he had for the Courthouse Square downtown-- close parts of the square to cars and create a "city market." While creating a mini-Pike Place Market might work, shutting down a part of the relatively busy square might be tough. The east and west sides of the square (Washington/Franklin and Jefferson/Madison streets, respectively) are the main routes in and out of downtown, and Southside is used to connect the two, so closing down any of those to vehicular traffic would be impossible unless the city wants to create gridlock and confusion. The northside of the square is less traveled than the other three, so that would be the only feasible location for a public market. Also, it just so happens to be where Sam and Greg's is located, so I'm sure they'll want to be part of their own project.
UPDATE 4/09: A website has now been launched--http://www.marketplaceonthesquare.com/