I've written another NagVis plugin, this time to help monitor printer supply levels. It goes in-hand with a Nagios plugin I wrote to query SNMP-enabled printers. All you need to use this is a network-enabled printer, the check_printer plugin from my site (below), and PHP with GD installed. This is 100% dynamically generated.
This image will auto-detect toner cartridges and size itself accordingly. Also, color order is defined by the printer SNMP order. Not all colors or features are supported on all printers. Color is determined by SNMP string. If you have problems, please contact me so I can update the gadget for your SNMP strings!
To install, simply place the print_supply.php file in your nagvis/nagvis/gadgets folder and enjoy!