I purchased a popout from Dick Crabtree and was very happy with his work. Talked with him on the phone and he answered some questions also. He sells them on EBay outright or he will rebuild yours if you already have one. His username on EBay is dikc. If he has any for sale this link should show what he has for auction on EBay.
You will find a post on Ford Barn 'SWAP MEET' selling a bunch of Pop Out Switches (about page 4). The fellow is in Texas; might be next door to you - so you might want to check it out.