A bibliographic for total syntheses of Vitamin B12 or any other cobalamin turns out to be fruitless. In fact, all references turn out to be to the famous historical synthesis, but I could not find much work (any work, in fact) on total syntheses, or even proposals for new synthesis routes. Not much was achieved since then.
This is partly due to lack of practical need. There are many molecules out there that are challenging to synthesize, and Vitamin B12 is currently produced at the industrial level by bacterial fermentation. From Wikipedia:
The species Pseudomonas denitrificans and Propionibacterium shermanii are more commonly used today. These are frequently grown under special conditions to enhance yield, and at least one company […] used genetically engineered versions of one or both of these species. Since a number of species of Propionibacterium produce no exotoxins or endotoxins and are generally regarded as safe (have been granted GRAS status) by the Food and Drug Administration of the United States, they are presently the FDA-preferred bacterial fermentation organisms for vitamin B12 production.
A good recent reference on the subject of its synthesis would be: K. C. Nicolaou and E. J. Sorensen, “Vitamin B12” in Classics in Total Synthesis, VCH: New York, 2003.