The alliance between Coinlab and Mt. Gox fell completely apart today as Coinlab filed a lawsuit for $75 million against the world’s largest Bitcoin exchange, as reported by Gawker.  Citing violations of their contract concerning access to the North American marketplace and foot-dragging over access to existing U.S. and Canadian customers that were to be migrated to Coinbase, the breakup deals a sharp blow to hopes for better exchange services for North American customers.