Hi,
How that I have the latest release of PBMS out the door I thought I would post some of the ideas I have had for possible ways in which the BLOB streaming engine could be expanded upon. 
What if the BLOB streaming engine supported the idea of having it's own BLOB storage engines that could be plugged into it the same way that storage engines are plugged into MySQL. The API for these BLOB storage engines would be dead simple, all they would need to support would be a 'get', 'put', and 'delete' method. The BLOB streaming engine would handle the reference counting and still provide the simple HTTP server for direct access to the BLOBs but the BLOB engines would handle how and where the actual BLOB data would be stored.
Currently the blob data is stored locally in blob repository files, which is very efficient but may not be ideal for some applications. Here are a few ideas I have had for possible BLOB storage engines: