A while ago I linked a fight doujin from a guy who, while not even close to the best of artists, had a lot of interesting alt ideas and fights. Dude's been updating quite consistently it seems with good stuff. Here's his set for Kyoraku's bankai, which is rather inspired honestly:
http://tommo2304.deviantart.com/gallery/42541194
http://tommo2304.deviantart.com/gallery/42541200?offset=24
Quite fun to run through to say the least. Also he's starting another interesting looking set with this, which actually is quite intriguing since it covers why the hell Hitsugaya was the only one to freak out about his spirit going missing:
http://tommo2304.deviantart.com/gallery/42541194
http://tommo2304.deviantart.com/gallery/42541200?offset=24
Quite fun to run through to say the least. Also he's starting another interesting looking set with this, which actually is quite intriguing since it covers why the hell Hitsugaya was the only one to freak out about his spirit going missing: