10-22mm is amazing tried one the other day at bestbuy.
I'm not sure if you have really looked into them but
on the cheaper side is the lens baby lenses SLR Camera Lenses for Nikon, Canon and more | Lensbaby Lenses
they have a couple inserts that will allow fish eye look
plus it will solve the issue luckless brought up of having a lens for only a couple of shots
I have the composer pro double glass....I really don't use it that often
but cool concept, no actual aperture you need to place rings down to act as one
and you move the lens around until you find the focal point you want.