Was going to link to this elsewhere, but
http://www.amazon.co.uk/gp/product/0...476136-6725516
Looks interesting, but I don't have it as yet. Not a Tolkien book as such, but Tolkien is referenced in the final chapter (check out the 'Look Inside' option) as being inspired by Norse literature.
Probably for Fans of Norse literature & Tolkien completists...