Are there any alternatives to kafka that are also modeled after the "message queue as a log" concept? In particular, I'd like to be able to reconsume arbitrary ranges of 'already processed' log/event/message data as well as trust the log as the ultimate deterministic source of truth for the state of the system.

The reason I don't just use kafka is because the "quorum" style scaling is overkill for our needs since the app will be for internal use only and will likely never exceed more than 1000 simultaneous users. Also, I've heard that zookeeper (required to use kafka) has its own technical overhead that I'd like to avoid dealing with if possible.