I'm a big fan of Ice Climber and seeing it on the "planned" list is intriguing. I always thought Ice Climber is a flawed game with great potential, It's sad it never turned into a franchise.
In my hack I put Mario in it and called it "Pipe Plumber".
It would be fun to mess with the source code and make a "Ice Climber 2" with new enemies, better controls and new levels.
Mishra made the 4 player hack so I suppose they sit on a whole lot of knowledge about the game.