This is the first time I've seen this particular myth posted on Free Republic, and I'm not going to just let it pass. It is taught in New York, I grant, due to the Iriquois lobby there.
However, I have never seen any actual documentary proof for it - I'd go so far as to say there is none. There is no evidence that Madison, or any of the other framers of the Constitution, was even aware of the structure of the Iriquois Nations, let alone was influenced by it. There were a few parallel ideas - and only a few - but that is a long way from saying they were a basis for the COnstitution.
I'd be interested in seeing what you profer as evidence for this claim. My own starting point in this is Arthur Schelsinger Jr.'s book, Disuniting of America - which was the first place I'd ever seen this claim, and seen it debunked. It is not on the web, sadly, so I can't give a link, but I'll see if I can find something on it.
Drew Garrett
"It would be a very strange thing if Six Nations of Ignorant Savages should be capable of forming a Scheme for such an Union and be able to execute it in such a manner, as that it has subsisted Ages, and appears indissoluble, and yet a like union should be impracticable for ten or a dozen English colonies." - Ben Franklin
"The only condition on earth to be compared with ours is that of the Indians, where they still have less law than we." - Thomas Jefferson, speaking of the Iroquois COnfederacy during the Constitutional Convention
"The fact is, that the condition of millions, in every country in Europe, is far worse than if they had been born before civilization began, or had been born among the Indians of North-America at the present day." - Thomas Paine, who was well aware of the Iroquois Confederacy, and wrote at length about them...
William Livingston, of New Jersey, spent at least a year, maybe more, living among the Mohawk (Iroquois) as a teenager - so, I'm pretty certain he would have been familiar with their system...
It is undisputed that Iroquoian leaders were present during, and participated in, debates when teh Declaration of Independence was in process...
I';ll have more examples later...