An interesting group build I'd heard of years ago was a build of older kits. Pre-80's, but you had to build with old school techniques. No rescribing, no photoetch, no 3D parts. Out of the box. Not as easy as you'd think, was a very common comment.
I'd be okay with rescribing around seams.
Fair enough.
Photoetch would be a group call. Some of the first PE I've saw was dated in the late 60's.
If y'all remember FotoCut, Fred's first PE was spoked wheels and prop hub bosses, from the 60's. What a great guy he was.
Definitely no 3D. I don't think it qualifies. Not against it mind you, it doesn't fit the theme.
But, yeah I'm good with anything goes. I'm in.
Time limit? 6 months? One year?
All you can build? Adversaries?
How about an Iron Man build?
Armor, Aircraft, Naval. You could replace one with a figurine build. Skies the limit.