Perry is incredibly... difficult to do. If you look at any cider book, it tells you that you need special perry pears that are horrible eating, so they are kind of rare. From what I understand, perry is a little tougher to make, too, as pears are so much more delicate than apples (softness, flavor, etc).
What most cider houses do is make an apple cider, stabilize it, and then add pear juice and call it pear cider.
That said, I did find some canned Bartlett pears that were just pears, water, and pear concentrate that I thought I would try fermenting, and then try something else when harvest time rolls around in the fall. I've had a pretty tasty Bosc wine before.