I found demo videos from Youtube about it:
from the Youtube video owner: 7" raspberry pi touchscreen tft hdmi 720p - I bought it on ebay from chinatobby2011 for only 45 EUR. The touch panel is called AT070TN92 V.5 and the HDMI AD Board is called VS-TY2662-V1 or PCB800099. I have made a screenshot from the ebay auction: goo.gl / hd9Nt The auction title is: "HDMI+VGA+2AV Driver board+7inch 800*480 AT070TN92 V.5 Lcd with touch panel"
raspberry pi resistive touchscreen with 7" tft over hdmi
The owner's another video to callibrate it, but it looks very well. I had to recompile the kernel of raspbian release 3.2.27. Raspbian already has an eGalax usbtouchscreen.ko driver module: http://goo.gl/n69Q1 which works with my 45 EUR touch panel (AT070TN92 V.5) + HDMI AD Board (PCB800099)