pop-top?

I stumbled across this innovative chap's mod to a Hiace (H200 I think)

http://www.motorhomeplanet.co.uk/archives/5192

and wondered - we already have the difficult bit done, I wonder if a couple of roof bars and a bit shaping on the cross pieces (shaped like a top-hat, to lie flat when stored and to pivot up when 'up') could give us a very low cost pop-up through the moon roof. And completely removeable too. One could even use a big solar panel on top.