A good example of a proportional (and thus multi-party) system that uses single-member districts is MMP[1]. You could argue, though, that this system doesn't fully keep single-member districts because some of the representatives are chosen from a national or regional list and such lists are effectively giant districts.

There is still much to be said in support of non-FPTP single-member systems, though, since they allow factions within a party to break off and present their own policies. Even if such a splinter party never replaced the party it split from, it could still prevent the bigger party from becoming too complacent and reliant on being the lesser of two evils.

[1] https://en.wikipedia.org/wiki/Mixed-member_proportional_repr...