As far as I know that's the only rom hack with multiple levels... Although, there are a few (<10) custom levels available such as a port of Shifting sand land from SM64 and a remake of 1-1 from the original SM.
There isn't a lot of activity in the SM3DL hacking community, I believe.
Anyhow just google"neo mario 3d land", click the first link and you'll figure out the rest.
EDIT: Just realized this answer came pretty late. Hope it helped you nevertheless.