Me and Hiccup (who i don't think is on this forum), have been working on a beta replica of NSMB, where we have remade beta levels from trailers, copied unused levels into the game, and putting in unused objects.
http://www.youtube.com/v/iUtuj6lE5Bk&hlhttp://www.youtube.com/v/oosiXRTQYug&h
http://www.youtube.com/v/tZDYcaxfilc&hl
http://www.youtube.com/v/Q4RR-5XFgeA&hl
Latest Version Download Link (.xdelta):
http://www.mediafire.com/?it2genyhndg
What's Done:
-7 Beta Levels Re-Created (Grassland, Underground, Mushrooms, Rope Level, Castle, 2 Desert Levels)
-One Test Level (Overwriting 1-A)
-Various Beta Tilesets Re-Created
-Beta ? Block Re-Created
-Unused Theme used as Main Theme
What's in Progress:
-Beta Blue Ring (Works on emulator, but not flashcart)
-Beta Kick (Animation has been found, I'm figuring out how to hex it in.)
-More Beta Levels to be Re-Created (Grassland, Tower, Underwater, Ghost House)
Not Started:
-Beta Co-Op Mode (Probably Impossible)
-More Beta Tilesets (Castle, Tower Desert)
-Beta Logo (To Replace the Title Screen Logo)