I have to say I like your kitbashes - I was rooting around for Samurai-related diorama stuff and I hit the motherlode with Canon's Hinamatsuri (girl's festival) 3D display here:
https://cp.c-ij.com/en/contents/CNT-0011649/index.html
It had nice 3D figures of the Emperor, Empress and 3 ladies in waiting at roughly 90mm (1/18) scale on the first page.
But in addition the following pages had smaller scale 3D models with what looks like a Goshoguruma and a Norimono - if you're lucky they'll already be in 1/64 scale. I was thinking of enlarging the Norimono to 1/18 and have it carried by a pair of guys recolored from here:
https://security.biglobe.ne.jp/mamoru/art/papercraft/