MIMF

Confirming that no-one makes a 1/4" TRRS/4 pole endpin jack and connectors. Anyone know of anything?

I'm thinking about setting up another guitar with a K&K Pure Mini Solo (pickup/mic) and a Sunrise and trying to avoid putting a 5-pin jack or two 1/4" endpins.

EMG supplies a 4 pole endpin jack with every acoustic bridge saddles system. Now if only someone made a 4 pole plug for it...
The current Apple 3.5mm audio jacks are 4 pole as well so that might be an option. There have been 4 and 5 pin XLR style jack around in the past but perhaps you should look to the future and see what the latest Apple headphone jack will look like when it hits the market with the next generation of device this spring. In the meanwhile you have plenty of other options off the shelf from Digikey and Mouser. How secure do you need it to be?