Schema for multiple identical queue tables
Answer originally left in comments by the question author

After reading up on partitioned tables, it seems that I could store multiple independent ring buffers in one since the partitions can be stored in separate filegroups, but I doubt I'm going to be able to sell the requirement for Enterprise Edition.

I am going to try for a poor man's partitioned table by creating pre-allocated queue slots in a single table using a clustered index on QueueId and SlotId.  As long as my queues don't grow beyond the number of allocated slots, I should be able to treat them as consecutive ring buffers for multiple logical queues.