@freqmax: I say A1200 style, I don't necessarily mean exactly the same. There is more than enough vertical height at the back of a A1200 to accomodate a standard ATX I/O aperture of 1.75" by 6.25". A quick measure up yields just over 2.5" of height. There would not be room for PCI cards, though.
Although a form factor of 170x305mm (the height of an ATX board with the width of a Mini-ITX board) would be a better use of space in such a case, and would be compatible with standard ATX cases as well.
