Still having troubles with the top. Plan is to to have the walls chamfered at about 45°, using 4 selftapping screws (two in the back corners, two near the front) and an extrusion to press on the battery.
Currently its 203 mm x 116 mm x 60 mm, which should fit on all i3 style printers.
edit: Having the battery upright would require channels for the wires, which kinda sucks. Laying it flat like in the other cases is easier, resulting in a new depth of 153 mm. Width and heigth remain the same.
edit 2: With some luck I’m currently printing the last test print. Material used is about 300g, screws are the same as the M2.5x20 used for the front panel.