The ESRB has rated another tower defense game for minis. The rating at the moment only mentions PSP, but I assume it can be played on the PS3. This game is on the iPhone and it is a flash game if you want a glimpse of what this should look like.
This is a strategy game in which players line up tower icons along a stylized 2D maze. The towers shoot out red blocks at geometric shapes that move through the maze, and players’ goal is to eliminate all the shapes as quickly as possible.
I am going to contact the publisher to see if I can get any more info.