Interesting idea. Tommy's pepperoni used to be curled up with pools of grease back in the day (60's - 70's) but not so much recently
I remember this style of pepperoni as a kid in the 70s as well in Canada. After decades of searches, I found it. It's referred to as "cup and char" pepperoni. How it works is the skin tightens as it cooks. As it tightens, the pepperoni becomes cupped, retains the oil, and the skin chars. It still a mainstay for pizzerias around western New York, and surrounding areas. Here's a link to the brand that makes them. http://battistonibrand.com/cup-char-buffalo-style-pepperoni-sliced-5oz-pack/
The folks in the deli at Wegman's (Buffalo) sell me a two pound bag that I keep in the freezer.
Below is a pic of the pepperoni on one of my pizzas