I'm one of those guys who only reads his email like once a month...unless there is something important in the works. Now either this guy is even worse than I or he got what he wanted from ya and is "done" and feels no need to tell you or he found someone else to finish or he just lost interest in the whole thing (which is pretty common). So I would say proceed as you see fit and do what you want - 1 month without response is pretty rude but I find that it happens a lot with unpaids as the people requesting unpaid are often on the young side and therefore impetuous and flighty like butterflies with the attention span of kids in a candy store.