I just found these too:
http://www.excelcomputerinc.com/html/xlsearchhinges.asp
With a laptop hinge I could put it externally on the case, but it looks like the Xenarc 7" has a connector on its side, which would get in the way.
I'm a little worried about the screen shaking a lot over bumps compared to a fixed install, but I guess the screens are pretty light.
I'm also thinking that the in-dash flip-out could be mounted some way down there. Hmm...