[Zope] Status of blobs and rdb plugged into ZODB

Hi. I have written a blob type product about a year or so ago and I remember at that time there was the promise of being able to plug different backends into the ZODB. This was to be one of the new features of ZODB that would allow some interesting things to occur. What is the status of this development. Are we there yet with ZODB 3.6 or is this still something that is not possible. It would be really great indeed if everthing was a proper object in the zodb with a choice of where it sits - whether in the zodb, filesystem or rdb. Regards, David