Thanks for the links, I'm definitely going to be making a few t shirts of these guys. i wish I could find a book that has a lot of these cutaways in it.
I've got a couple of cheap near-gachapon kaiju toys that have cutaways with clear plastic covers that get put over the cutaway. Cheesy, but fun.
I was randomly looking up old model kit illustrations, including the work of the ever amazing Shigeru Komatsuzaki. This then brought me to this excellent posting from Pink Tentacle, and I was reminded how much I miss the site. Hours spent perusing amazing images from Japan. To whomever maintained this, I cannot thank you enough for the enjoyment you have given me. A few selections from the link, but if you are unfamiliar, do yourself a favour and google Komatsuzaki's work; you're in for a treat. And for a real bonus, I suggest continuing on from the bottom of these and taking a scroll through the comments. Brilliance, if ever it existed.
Twitter thread by Matt Alt about the king of cutaways: https://twitter.com/Matt_Alt/status/1618777954611494913