Ask HN: Making Bitcoind / litecoind / dogecoind multi-seat

I'm looking to make an ecosystem for building multiple apps (by multiple developers/teams) that can work with Dogecoin on a server, but I've hit a wall in how the Bitcoin server RPC API and its descendants are all designed to interact in effectively a single-user mode (every call acts on the same "wallet").

Would it be possible to put a server in front of a bitcoind (&c) instance, that could track the state of multiple users and limit them to API calls that could only affect themselves? And, if so, would that server need to run any bitcoin-specific logic (ie. logic that wouldn't apply to Litecoin, such as block rewards or SHA-256 hashing)?