I think your best bet may be to find turkey pepperoni in stick form and cut it a bit thicker than normal.
Modernish is not entirely correct. It actually has more to do with how the casing is stuffed than the casing itself. A pepperoni that cups generally doesn't need the casing on to cup.
We get a bit of a warped perspective here. In the real world, most people prefer pepperoni that lays flat - not that they ever think about it. Most pizzerias certainly do - not because it tastes better, it doesn't, but because the same quantity looks like a lot more pepperoni on the pizza.