Do you know if it is possible to buy just a simple rec start button working on the lanc protocol? It is for adding the rec button on the handle of my shoulder rig. Every LAnc controllers I fond have lot of cool functions (but useless to me) that render even the smaller one, somewhat bulky.

I just need a simple single red button! Is there something like this on the market?

Yes there is. I have several of them.

Viosport wired LANC remote controller (http://www.creativevideo.co.uk/index.php?t=product/viosport_lanc_remote)