There's likely a number of channels that's burned into an eprom, so you won't likely be able to change that, but you can probably change the code that it checks. How good a developer are you? You can telnet into the units, trace the code as it runs line by line to see at what point it checks this and maybe patch the code in the machine to bypass this check or return a different value. If not, you can always get another 8 channel NVR and run their CMS software to see all 16 cameras at the same time on your PC.
