I know this post is OLD.......but i'm gonna reply anyway!
Dual alternator's?...Why not! go for it! Some vehicles have Dual batteries added, other have dual transfercases. Heck I have even seen vehicles with dual headlight, and some with dual rearwheels. A couple at a car show had dual exhaust, dual carburators, and dual bucketseats! They were very nice too! Shiny..clean...pretty!
Shoot come to think of it...that tornado chase vehicle the "dominator" owned by Reed Timmer had dual windshields and quad windshield wipers!
( And he got smart finally! Dominator 1 a chevy tahoe, dominator 2 was a GMC Yukon XL, and now Dominator 3 was built using a FORD super duty!)
Some people even have Dual Citizenship!
SO yeah! Dual it up! the world's your oyster!