We have a need to use multiple client names with StackExchange.Redis, which as far as I can tell means multiple connection strings and multiple (static) instances of ConnectionMultiplexer.
My current thinking is to create a static wrapper class and use a private dictionary keyed by client name (or the whole connection string) to store the multiplexer instances, and expose a single GetDatabase(name) method which looks up the multiplexer (or locks and creates it) and returns the result of the GetDatabase() call on the instance to the caller.
This was the first thing I thought of, but I wouldn't be surprised if there were a better way to handle this requirement.