Why not go for a carbon skin to fit over the existing roof? im sure phil did one for twins, all you would need to do is weld a blank on the top of the roof and smooth, then the same on the inside and fit a non sunroof headlining. Plus I would expect the roo to cost about £250 - £300 tops as there would be no core just fabric?

If weight saving wasnt the purpose and hiding thew sunroof was then I think this is the best option.

Jay tell them what you explained to me when you lifted the car up one side before and after you cut the roof

Interesting thread this