Hi abdullahseba
You could try Arrow embedded
http://www.arroweurope.com/.
I got some displays and capacitive touch in 7" from them for prototyping a machine HMI, I don’t know about low volume, but I got 3 pcs as initial samples for the design phase.
the touch driver board can be ordered with USB or I2C interface
and the touch driver is compatible with linux 2.6 kernel
just checked the website, and they have 155 items identified as touch screen - so it might be worth to give them a call, might not be cheap though
br Ton