I'm really interested in this project and was wondering has happened? It looks like only 1.5 months ago there was a lot of talk about starting it up full force.
I'm the current TMNT speedrun record holder, looks like someone uploaded to youtube here: http://www.youtube.com/watch?v=dFukw68Y5nI
and I'd really like to make new hacked rom that's great for speedrunning and normal play as well. There's so many neat things you can do in this game but they don't come up in speedrunning or normal play much if at all. I feel as though with better levels this game could be so much more interesting and involved. I really see great potential for this and some speedruns/TASes could help popularize the level editor.
Dan's cowabunga level editor is already pretty good. If it could just delete/add special items, and I don't know if it can choose what enemies you add, I'm only able to add the mouser enemy; you'd really be able to do a lot with it. Then if the ability to edit stuff like: overhead levels, entrance/exit locations to levels, level size/geometry, special events such as sub-bosses/bosses, damage/HP, frames required to hold jump to execute the three types of jumps (oddly specific but I feel as though this could be a lot better)- this could really give you supreme control over the game.