I could go a couple of ways. For a classic two-gun arrangement I would choose a magazine rifle in 300H&H (Ideally a British classic Mauser) for plains game and a Krieghoff Big 5 in 500NE for the big stuff (I like the K-gun design which makes it perfectly safe to slog around loaded). For a minimalist approach I would go for a Dakota 76 Traveler in 338LM/416Rigby.