The roof has dormobile style features, but isnt quite the same as mine:
Normally have two windows side by side (which this has) then two roof vents/skylights below (this has a big window).
It appears to have dormobile style struts to hold it up, & reinforcing plates in roughly the same place a s a dormobile.
The lines of the roof look slightly different to my dormy though, perhaps someone has modified it? or its a non-vw conversion.
Look at the commer(?) van top left on this link:
http://www.dormobile.org.uk/index.html