[Lalwendë]

It's not entirely true that no other writer has been allowed to publish material based on Tolkien's work. There was The Fall of Gondolin by Alex Lewis. However, and it's a fairly big caveat, he directly asked for the approval of Priscilla Tolkien (some say, it was perhaps a fait accompli that she was presented with - the Tolkien Society is rife with gossips so who knows...) and it was limited to a strictly private publication of fifty copies only!

Don't be put off though, fan fiction is worth doing. I've had fun myself on this site, taking part in our RPGs, which are often based on developing unfinished ideas/tales (take a look, they're great). And if you want more recognition then use it as a basis for your own creation. If it's an original idea then it may well stand a move out of Middle-earth and into your own created world.

There is one Englishwoman currently making a mint out of her altered fan fic of Twilight. What she wrote in my opinion deserves nothing more than hearty belly laughs, what you propose sounds much more interesting and if you can turn it round and make it your own I'm sure it should be good.