Do you build cannons for hire at all?
No, I make them in my limited spare time (still working for a living.) The closest I come is teaching the upcoming cannon making class at Lassen College (June 25-29.)
If I did make them for hire, I would have to charge at least $50 an hour and that makes them too expensive for most people. I usually recommend the other cannon makers listed in the advertiser section at the top of the forum. As far as I can tell, they are all competent people who will do a good job. If they need plans, I can offer them.