I nominate Yifu Guo.  The avalon chip sale fiasco cost a lot of people a lot of money... and he certainly had enough funds that he *could* have done the right thing by his customers. Instead - he screwed over the end users as well as a number of promising miner assembly businesses.


Also - Eduardo DeCastro of HashFast.
Hashfast delivered late on initial batches, and then not at all.
A flowon casualty was the IceDrill project which was due to receive a large number of hashfast units.