I found this video which claims to be the first level of Super Mario Brothers 3 done with legos. I counted the frames and I see about 5 frames per second which would be a total of 160 frames as the video is 32 seconds long. The sheer volume of legos that the person that put this togather had to move to represent each frame is amazing. I don't see movement around the edges of the frame where the legos are so I don't believe they used multiple trays to put the legos on. I'll wager they did use some kind of scanline system where all of the legos in a single horizontal line were attached to a single piece so they could just move the entire line over to the left one space in each frame (plus whatever changes from Mario crossing the scanline).

Check out the video of the lego Super Mario Bros. 3 level below or click over and view it on the host site.

Source: Google Video