Regarding the following section:
What make and model is my printer?
Each different printer has a model-specific Device ID. ... you can do it yourself with the lpinfo command:
su -c "lpinfo -l -v"
Actually, "lpinfo -l -v" gives you the information from the PPD file, which may or may not actually match the print device in use. It doesn't actually collect any information from the printer itself (expect maybe with IPP Anywhere -- I haven't played with that as much as I would like to have).
Hi Bryan - actually it does - if you start 'su -c "lpinfo -l -v"' and you catch network traffic by f.e. wireshark, you can see snmp or mdns packets with queries on variables you see in output.
You are, of course, correct. "lpinfo" does query stuff over the network. I'm not sure what I was thinking when I wrote that (maybe "lpstat").