Well, it wouldn't be allowed in the Extras* repo, legal or not, until Nokia verifies that it is "legal enough" to not draw another or additional points in the ongoing lawsuit from Nintendo. I suspect that function to be infinite.

Legality isn't even the issue these days so much as how much litigious risk is one willing to take, and the bigger the fish, the more appealing target it makes. Nokia should probably maintain a fairly low threshold so that they don't have to waste resources dealing with niches when they have their own bigger fish and fruits (Apple) to fry--which is what they did by taking Nintendo emus out of the official maemo repos.

So anyone is free to port the emu, but they would do so knowing it would have to live in a third-party repo.