Update: it seems that this hack was found by Trekki, Tanks, Sonicandtails and other “NSMB hackers” too, along with the version of LucaPM and other gamers. You can download the Trekki version at http://treeki.googlepages.com.
LucaPM was working on a “beta-hack” to restore more removed stuff from the game. The beta revival would have had all the secret levels playable plus some more from the early Mario Bros DS tech demo and the E3 beta version, the removed “traditional” 2 Players mode in the levels and mega goombas.
Some info about the “beta-hack”: how you probably know, there are 5 unused levels in the “Final NSMB game code” that come from the beta version of NSMB :
One of the desert levels is probably the oldest level in NSMB because it’s showed in a video of the beta NSMB at the E3 when the old tileset were used (NSMB was still a concept). You can see the video in the NSMB beta page of Unseen64 :) More infos about the beta levels and the tech demo come from Youtube and U64. Some beta-levels are completely shown so the reconstruction should be affidable and accurate, but others will be incomplete because there are not many more informations.
Here’s the download link for the semi-beta of the beta project: http://lucapmspace.blogfree.net/?t=2121216
U64 is an archive with articles, screens and videos for cancelled, beta & unseen videogames. Every change & cut creates a different gaming experience: we would like to save some documents about this evolution for curiosity, historic and artistic preservation.