Based on the work of John, M0UKD, I've build a small sensor-keyer. I used a surplus aluminium shelf and two aluminium stand-offs as "paddles".
See the evolution of this project here.
Here you find some pictures of the keyer-unit:
This sensor-unit works suprisingly well and interfaces excellent with all my Elecraft transceiver.
I ordered this head immediately. It was delivered in record-breaking 2 days after ordering via their web-shop.
The build quality is excellent. The head can be fixed with one central M3 screw from the rear-side. Problem with this kind of fixing is, that you can rotate the head with little force. I would suggest, that either the head must be mounted with two screws or the head should have an anti-rotation pin. As the head is made of "plastic", you cannot force the screw tight enough - or you simple use a little bit of glue ;-)
The new BaMaTech head works fine - but - I usually touch the left paddle a little bit from below and the right paddle a little from above - and as you can see in the pictures, the contact areas are surrounded by black plastic ... hm - let's see whether I can handle this ...