Sync Gateway Load Balancer alternatives

There are a number of different options for Load Balancers in from of Sync Gateway. In this page, we focus on NGINX as the main example, but this may not be applicable to those who want to use other solutions (e.g. HAProxy).

It'd be nice to have some more examples, but this might not be practical to scale. Instead, perhaps we could talk more about the generic requirements, and then pick one or two products to demo how to set up those requirements?