For TG-16 import conversion, you have to swap four pin connections around. I've seen four-pole double-throw switches on some telecom devices, but it's not a component you're going to see lying around at Radio Shack. You could do multiple switches or maybe a relay, but it'd be hazardous if only some of the pins were switched and not all of them. Hope that's helpful.
-KKC, who cut through all the Turbo import conversion by just having one of each console.