Here is my ad replacement for the new Marlins Ballpark stadium. I am sure they are not accurate becuase I have not seen a lot of current footage of the new stadium yet. I used the ads from my Marlins Field (CAS) Stadium I made for MVP Baseball and created some of the ads such as the Majestic/jersey ad. As you may know, I typically cannot stand generic ads in the stadiums so I am using this for right now.
Just copy the included .iff file into your main MLB 2k12 directory. This will replace the existing Marlins stadium.