Christopher Tolkien has edited into a "completed" work his father, JRR Tolkien's - you know the chap who wrote Lord of the Rings, The Children of Hurin.
I am not quite sure what "long version" means. A lot of Tolkien's early work is alliterive poetry rather than prose. If its a prose work I'd be interested. Well it will no doubt attract alot of interest. It is set much earlier than Lord of the Rings and The Hobbit.
Christopher Tolkien was behind the Silmarillion and he put to together the 10 volume history of Middle Earth. Another work he put together is Unfinished Tales. This is a collection of notes about the History of Middle Earth, later chapters deal with the coming of Gandalf and Saruman, Black Riders and there are other versions of the search for the ring. I found the later quite interesting. I've never read the 10 volume history.