Drilling or Combo gun as an alternative to a Double for Plains Game?

Though I'd love to go out and pick up a nice used double to use on Plains Game as a sentimental act- it's not in the cards financially right now. Like most, I too grew up reading the adventures of many of the great hunter/writers who used a Big Ole' Double Rifle on their Dangerous Game, and it would just be a great sentiment to hunt a Zebra, Warthog, or heck, any Plains game with a nice double.

But lately I've been very interested in the idea of using a 3 Barrel "Drilling" (2 Shotgun...

Drilling or Combo gun as an alternative to a Double for Plains Game?