If you want the ultimate in variety AND "redundancy", get a Contender!
Same frame, grip and trigger pull every time, literally dozens of calibers to choose from. Different barrel lengths and styles too!
I have Contender barrels in 6", 10", and 14" lengths, some round, some "bull", some lovely tapered octagon profile. Calibers from .22LR to .45-70!!
It don't get much more diverse than that, and keeping the same frame means the redundancy factor is appeased, as well.