http://handwerkhoekje.punt.nl/

I believe that site is no longer viable, this one above is not American, you will have to scan around, but write to her if nothing else, she speaks quite good English, and she may have something not already listed on the site, as it is under construction. She does some mighty fine work.

I have used her quite often, there aren't a lot of graphs for musical instruments out there, but I do have a few on the machine, if you would be interested.