I think one of the Kegs racing catalogs had a picture of a 63/64 impala with a Dodge or desoto roof welded on looked very cool!
it was a retro redo of the 61 style bubble tops grafted on to the 63/64 square tops (fake convertible versions).
It was called the impala sports roof. Here is another link:
And here is a link w/pictures on how it was made very cool:http://www.penfounddesign.com/Projects-ImpalaSR.htm
The 1963 Impala SportsRoof made its debut at the 2006 Detroit Autorama, and was selected the Super Chevy Pick Of the Show. From there it won a Fab Five Pick at the Goodguys Great American Nationals, Hershey, Pennsylvania, 2006. It received "First In Class- Lo Rod" and a "Special Judges Award" for the vehicle that "best exemplifies the lowrider movement" at the Lowrider Magazine Tour Stop in Indianapolis, Indiana. During the summer of 2006 it received numerous Super Chevy awards, including "Best Full-size 1958-1964 Car" and "Top 8" at the Nationals in Indianapolis, Indiana. At the Goodguys Nationals in Columbus, Ohio, it received both a "Rod & Custom magazine Top 10" and "Boyd Coddington Pro's Pick". The car was featured in Custom Rodder, Super Chevy and Power magazines and was shown in event coverage in Super Rod, Rod & Custom, Custom Rodder, Street Rodder, and several other publications. American Racing Equipment, Inc., selected the SportRoof for its booth at the 2006 SEMA Show in Las Vegas, Nevada, and the car was also on display for three months at the Wally Parks NHRA Motorsports Museum in Pomona, California at the end of 2006. In 2007 it was featured in American Racing Equipment, Inc., advertising and catalogs, was a cover photo for Jeg's Performance Products and Pace Performance catalogs, as well as Newstalgia Wheel
HTH - Dave