Re: disconnecting means for industrial control panel
409 is the correct article for industrial control panels.
409.21 says the overcurrent protection can be upstream or integral to the panel. A "local" disconnect is not listed as a requirement.
Industrial control panels themselves do not follow the same rule as motor circuits.
409.30 refers you to part IX of 430 if there are motor controllers internal to the panel. In particular 430.92 covers motor control centers but again this only deals with the overcurrent protection not a "main" disconnect. The exception to 430.112 is the allowance for a single panel disconnect to be used instead of individual motor disconnects.
Just because you can, doesn't mean you should.