Wheels & Tires - Wheel measurement question

if a person were to get an aftermarket rear end and have it narrowed would that allow them to run a wheel with a different backspacing? i love the way the dish looks on this car and would like to achieve something like it but dunno if its possible or not. any thoughts?

http://www.camarogenerations.com/memberfiles/muleext.jpg

Yep, that would work.