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.
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...