Sounds like you are building a new service, and using the old service equipment as a subpanel. If your new panel is service rated, and we all know the "6 switch on services" rule, I don't see what the inspector's problem is. To me it doesn't matter that more that 6 breakers could be installed. What matters is, that you install 6 breakers or less. We all know that only trained persons will be working on this equipment, and if a person is trained they should know the "6 switches or less" on services rule. So, the inspector can't assume (and we all know what happens when we assume things, it makes an a$$ out of u and me) that someone is going to, at some time in the future, break the rule by adding another breaker. Sounds like a job for Sam Colt.
No offense to any inspectors out there, or to you junkie. By the way, junkie, how's your game?
At your Service,
The Watt Doctor