'60 Dodge tail lights bolt onto a '55 Ford and they're real neat, they're hooded, they kinda match the Ford headlight bezels.
Mercury station wagon lights were the old standby back in the day but they are like hens teeth to find. You could french the round lite and make the fin slope down towards the round light at an angle. Roger beat me to it..
1961 Ford lenses look like a good fit, and are available with and without back-up lenses. They range from $25-$50 a pair on EBAY. You can ask a vendor the diameter to make sure.
63 Fairlane SW. Mounts right in and gives it a "sunken taillight" look. Need the whole taillight ***embly though.
I heard someone was making repops of the Merc wagon lights in all plastic (including the chrome bezels). Not sure how much they cost but if they're all plastic I can't think they're real expensive.
How about the old standby Lee lenses? http://www.leelenses.com/products/ kool rides has lee lenses as well as the full Merc reproduction in fibergl*** http://www.koolrides.com/store/index.php?cPath=2_80
I have the lee type smooth with a slight peak taillight lens that I just bought I'm not going to use. If you want them you can have them for what I paid. I'll eat the shipping 50.00 thanks