I have a similar spare wheel from a Crown Vic that I use with my 1947 teardrop trailer. I opened up the center hole so it would also fit on my '64 wagon and I actually had to use it on a long camping trip when a tire went bad on the wagon. The wagon has the original spare in it so I didn't want to risk it. I used the Crown Vic one because I needed a 16" wheel that would fit over the funky suspension that fits inside the wheel on the trailer. I guess I should pick up a Jeep tire so I can get some height like you did.

This one isn't really that easy to find as I found it only came with a certain handling package on the Crown Vics and such. You can also get a version from the bustle back Lincoln Continental in the mid-late '80s. It has spokes instead of holes and seems to weigh a bit more. I have one at home I can take a picture of.