Ethernet cable (a.k.a., CAT-5/CAT-6 cable) is perfect for extending your I2C sensors using the LTC4311. By doubling up the eight conductors we can get a nice, clean signal to run upwards of 100 feet / 30 meters of distance!
Here's a nice way to connect your STEMMA QT devices to the Ethernet cable, using some hookup wire, heat shrink tubing, and a pair of RJ-45 adapters.
Slide the tubing over each solder junction and heat shrink it in place.
Now, you can plug in any length (up to about 100 feet / 30 meters seems to work well) of Ethernet cable, and then plug the STEMMA QT cables into your sensor on one end and the LTC4311 terminator on the other. Connect the LTC4311's other connector to your microcontroller and you're ready to go!