That does sound like a fun extension of the hobby. I wanted to branch out into something "non-gun" and started bayonets but then they suddenly became popular and expensive. Then it was ammunition. Same thing happened. Last attempt was field gear. Have you checked the price of an original M1913 cartridge belt lately? If I start collecting toy guns you likely won't be able to afford them because my collecting-curse will drive the costs through the roof, haha.
I gave up on all forms of collecting. I'm content looking at pictures of other people's collections on the internet and daydreaming. It is like my childhood when I would longingly look at the Sears or Service Merchandise catalogs before Christmas dreaming of getting a Navarone Mountain army play set or better yet, real gun. I think I wore out the gun pages of every Sears, Montgomery Ward, and Service Merchandise catalog that was delivered.