"It uses the original design of the CMA range throughout. The AR-6 is the CMA-10 but brought up to current audio and build quality standards "
The old schematics are not hard to find, yes some parts used are obsolete today but if you have access to the mixer you can just see what they replaced them with. So i don't see a problem with not having access to the AR-6 schematics, anyone that have the skills to repair an original Bozak should be able to fix the AR-6 also. Guess the biggest problem is finding people with these skills today.
Developing something like this and build a sucessfull company around it requires a lot of money. For a small company that would normally require to get some investors, if you release the schematics etc. i think it would be very hard to find anyone that would invest in it. A larger company that can afford to spend like $100K-$200K in R&D, manufacturing and sales related costs easy might think different.