It seems that Gavin Menzies is not the only person who claims that the Chinese discovered the Americas before Columbus.
Paul Chiasson, a Toronto architect and amateur archeologist, claims that some ruins at Cape Breton are indeed due to Chinese navigators who circumnavigated around Africa and came to Cape Breton and settled there. He claims that Mi'kmaq natives were culturally influenced by those alleged Chinese navigators too.
He published a book called The Island of the Seven Cities: Where the Chinese settled when they discovered America furthering his claim. Here is the Amazon summary and reviews.
A web site for the book is here.
What is ironic is that Chiasson has contacted Gavin Menzies and worries that his work is lumped with Menzies and both being described as fiction, just like Geoff Wade did for both.
More rebuttal of the book can be found in the 1421 Exposed web site by various experts.
Five provincial archeologists have refuted Chiasson's claims in this CBC article agreeing that there is no evidence of human settlement in the area, Chinese or otherwise.