A few years ago I built a hub for a number of temperature sensors, based on the DS1820. Although computers with serial RS232 interfaces become extinct, most server machines still have these connectors, as they are useful for remote console management. The combination of a few DS1820s and the serial interface offers a very nice, cheap way to connect multiple temperature sensors to a monitor.
Another customer liked the hub smaller, so I used the exact same circuit to build two smaller units for just two external sensors. The internal one remained, so each unit has three sensors. I saw no reason to change the proven design with the metal 6.3mm jack plugs. These sturdy capsules and the brainless extension cord option really are winners. Add some tie wraps to attach everything to your equipment racks, and you have a very good Nagios feeder.