I spotted the word in question in the free City AM newspaper this morning in an article on the merger of Lloyds TSB and HBOS. I quote:
The marriage of the pair sees the combination of expertise in several specialist areas, creating a superbank, or "Bankenstein", as one analyst put it.
Obviously 'Bankenstein' is a portmanteau of 'bank' and 'Frankenstein' (Frankenstein's monster is pictured below, gesticulating in what appears to be some kind of shop).
UPDATE: I've found a web version of the City AM print story – the 'Bankenstein' quote can be found in the third par down.