This is my first idea.

The wedge shape gets it's rough dimensions for the wedge area (to the left of the sketch) from the Pipo x8 as envisaged. The width of the entire case will almost be double that of the x8, however. The right side (the extension part, as it were) will be an open top; the back, bottom and side will retain the shape of the left side. I may consider a hinged lid for storage.

I am still very open to suggestions, however :-)