Here is what I have come up with for the i3v10" Y-Bed. I have not tested this yet, but figured I would print about a portion of this in plastic diagonally on my printer to verify the wheel hole spacing & holes where heat bed attaches. I am not sure when I will get around to using this, but since we were on the subject in this thread, thought I would share it with others to see if it was useful or if someone had suggestions for modifying it for less weight. The size of the wheel holes work for plastic, but not sure if the same size will work for aluminum.
Y-Bed_i3v10_rev2.dxf