I know how you feel! I got bit by the tinplate bug really hard just as mth was getting out of it for a while, plus the lct agreement was ending. Everything old eventually gets new again, so I am sure reproductions will start again sooner or later, though as folks have said it don't count on sooner. And that was before covid-19 trashed the world economy.
I was really hoping for some tinplate style trains with modern controls but in updated styles, such as a 2-6-4 in O gauge, maybe some full body tank cars but with shiny brass handrails or -gasp- tinplate wheels in tin truck assemblies with actual bearings or needle point style bearings. (Oh the horror of not having to oil all the cars every few weeks or so - just blasphemy I tell you!) How about a factory made Flyer brass piper shrunk down to O gauge?
How about a tinplate or diecast steam switcher with working tinplate couplers on both ends? (preferably with a slope back tender or a saddle tank style unit!) I would even be okay with a tinplate style GP-9. Heck with how easy it is to double head loco's with proto-sound electronics, why not offer factory made front couplers assemblies for the traditional 263e or 259e style loco's. So much potential, but honestly such a small market.
I love what you are doing. Can't wait to see your new switch towers in service, actually being used to control things.