Nice work Ignacio !
You know I like your ideas, I’m still using the “clothespeg paddle” built after your idea
(Homebrew mini CW Paddles and Video)
But I think I beat you for weight with this one …
By coincidence, I was just finishing this morning a mini paddle for my newly built QCX transceiver.
(more pics of the transceiver here : Qcx qrp rig - #31 by ON7DQ )
My newest mini-paddle WITH CABLE weighs just 14g 
materials : pieces of PCB , two relay contacts, 1 bolt and nut, two small pieces of plastic from a pushbutton as fingerpieces, cable from cheap earpiece with a right angle connector, black plastic as a rain cover, superglue.
Paddle is “sticked” to the QCX with “blue tack” (but mine is white hi)
73 Luc ON7DQ