Simple and to the point.

6.5x54 Manlicher schoneor (mountain rifle)
300H&H Dakota76 (plains rifle)
9.3x74r Chapuis sxs (bush gun)
416-500 Searcy boxloxk dlx (DGG)
20g3" Win model 21 26"brl (upland game)
12g3" Arrieta 600dlx 29"brl (waterfowl)

How could you possible beat it?

Maybe an all english best double battery?

318W.R. westly richards sidelock sxs w/scope
350r rigby boxloxk sxs w/peep sight
450/400 3' jeffery's sidelock sxs w/QR scope
465/500 holland royal sxs w/express 50m
20g boss round action 27" brl
12g purdey best game gum 29" brl

Ya that would be it if I had a spare 400,000$ lying around.