According to this, N+ co-creator Mare Sheppard has confirmed plans to release three downloadable expansion packs for the ninja platformer, each containing about 200 levels, in the coming months.
The first pack will likely contain easier levels and some co-op multiplayer levels and could hit XBLM in as little as three weeks. The second and third packs would follow soon after.
"The other packs will probably contain harder levels, race and survival multiplayer, and some classic N levels from the original game," Sheppard said. "We're just not sure how the content will be distributed among the packs yet."
The content will be priced at 200 Microsoft Points per pack or one point per level, and one of the packs will be free.