Williams patented some of their cabinet designs -- the Joust cocktail for sure.
Having said that, I don't expect that anybody will give you problems, although there are a number of people doing this -- some using wrong information (and now cyber stalking and bullying those who have revealed him for what he his) and some doing a great job.
If I wanted to enter the market with something like this, I would talk to DPTWiz over on KLOV as he has good CNC plans for a number of cabinets (Joust cocktail included!) and was looking for folks to produce his kits locally in their regions. If you need someone to vouch for you (tKLOV changed the registration rules due to the aforementioned stalker/bully), drop me a PM here and I will take care of it.
EDIT: Just noticed you are a Canuckistanian -- Terry, is that you ?

If not, there are some folks in Canada who have looked at doing the same thing.