Yes most mechanical discs have one stationary pad, and flex the disc slightly,
if properly adjusted, that is barely a MM.
IRD sells a dual banger mechanical that has a mechanism
to come at the disc from both sides.
Goodridge is a manufacturer of hydraulic stuff and can be used on bike brakes
http://www.sjscycles.co.uk/goodridge...ear-prod11435/
I think the company is actually in the US.