This is my client. It connects my winkey V3 at the remote to my winkey V2.2 next to the radio. The paddle plugs into V3 and V2.2 plugs into the radio. Here is a video of performance
It's OK for rag chewing or casual DX but too laggy for pileups or contests. The lag is not due to the Flex. My lag in the Flex circuit is microseconds. It's a fairly expensive solution (two keyers needed) for fairly mediocre performance.
Another solution suggested by Enzo IW7DMH is a Arduino setup he created. In this setup he takes a standard Arduino Uno R3 and an Ethernet dongle to connect the remote computer. The Arduino resides next to the radio and is plugged into the radio's CW port and the local LAN. On the remote computer the key plugs into a serial port and a little program on the remote computer connects the Arduino to the key. I haven't built this circuit yet but I have the parts on the way from China. Total parts cost plus shipping is under $10. Here is a video of Enzo's creation in action.
Once I get it working I will update. In the meantime I'm trolling 40 CW!!