I have earlier tried to convince the developers of GH to make a special ghx file format (.ghxvc) with all the logically irrelevant info stripped out (like layout positions, date/time and thumbnails etc) and all remaining info, strictly sorted so as to be suitable for version control. (the vc part of the .ghxvc file extension)
One of these days someone is going to make a script that strips out the messy info that makes version control meaningless (yeah, this was meant as a threat 
)
Layout-info etc should be kept separately, either in a separate file (hm…) or padded on to an end section in the .ghxvc file so it would be easy to strip out, and to merge again on file open, without messing the whole thing up.
NIHS (Not Invented Here Syndrome) seems to be an obstacle though. 
// Rolf