N+ always intended to let players upload custom levels for anyone to download, but Microsoft nixed the feature at the last second.
The decision was so last second, in fact, the version of N+ available on Partnernet, a test version of Xbox Live that publishers and select media can access, actually includes this feature. MTV Multiplayer wondered why a small studio like Metanet Software would bother investing in such an ambitious feature if they had any suspicions it wouldn't make the cut.