The nice guys at Future Electronics put a lot of energy into bringing a 7 inch multitouch display to the Wandboard and even posted the schematics of their board.
Some movies on Youtube:
***What do you need***
Future Electronics : FWBADAPT-7WVGA-PCAP adaptor board purchase page (the schematics can be found here as well)
Future Electronics : 7 inch multitouch LCD display
And of course you need a Wandboard Solo/Dual/Quad.