You know.. sometimes it’s good to be right :) The G18C from TM certainly seems to be the latest play thing for folks to make spare parts for. Freedom Art have added a new scope rail for the G18c mini AEG to their pages today. The new rail simply replaces the rear sight mount and bolts onto the top of the slide.
As it’s not a blowback unit there’s no huge problem mounting a scope rail on the top, although you probably wouldn’t want to swing off the rail, as only mounted by the rear sight it’s not going to be fixed on that well. Price is 2,800Yen and it’s set for a Janurary 25th release.