>>6674954Not sure if its your thing or not but the Pegasus hobbies 1/144th Nautilus kit might tick all the boxes for you. Its not mecha but Ive been thinking about buying one for a while, it just looks like so much fun to build.
it has shitloads of pieces, photo etched parts, a super detailed interior near the main windows with a whole 30's style ballroom & grand piano all lit with included LED's and a sweet giant squid model as part of the base.
HLJ have it for 9440yen which is cheap for a kit of that complexity.