There is a commit working its way through CI right now in the 1.3 maintenance branch. This commit puts in place a mechanism to inline many different types of URIs directly into the statement indices, including UUIDs. The new mechanism and how to use it are described in the ticket:
This change will be backward compatible with old journals, but obviously to take advantage of it you would need to reload the data so that URIs can be inlined. It should be possible to inline all sorts of URIs with this new mechanism. Inlining terms is a great way to save space in the indices and improve performance, as it eliminates the need to round-trips terms through the dictionary indices.