Nike Cortez Shoes
Nike Cortez Classic shoes for Mario, Luigi, and Dr. Mario.
The .zip file includes the files to replace:
Mario's neutral costume (PlMrNr.dat)
Luigi's neutral costume (PlLgNr.dat)
Dr. Mario's neutral costume (PlDrNr.dat)
I've also included the .png's for the textures for the shoe bottoms, the specular map for the shoes, and the shoes itself. That way, you can fire up DAT texture wizard and use them with a different costume. Just remember to change the file names accordingly.