Joke at work about hanging... did I overstep the mark here?

I would say your worrying about nothing here, it sounds like they all liked your joke, and i must admit it was very funny, very quick witted, you were just playing off the architects initial remark. However, im not sure what the contractor laughing especially hard had 2 do with him making his payment late? I think if you brought it up, you would end up embarring yourself for no reason, forget it :)