Converting figures and Dioramas

I've never worked with 1/72 scale figures so I don't know. Seems awful small. I do work with 1/35 and 1/48 scale military figures and have redone, reworked and converted them to suit my modeling plans and ideas. There are a few books out or were on modeling nd converting scale figures.

Yeah they had all of those creatures. I had that one, along with Fort Apache and the WWII one. Best toy soldiers around. I think I ended up using the strtcher crew in one of my early dioramas. The equipment was authentic, except for the Germans. IIR, they all had crude G41s, though they weren't that far off. Those were the days.

Pegaso has a 54mm Neanderthal man carrying an antelope skull. Probably a bit pricey for your application. The 1/72 stuff would be extrememly hard to work with. You're best bet would be to look for a play set based on the old Marx sets. Do a search for Michjigan Toy Soldier and Hobby Bunker. They both have good selections of these toys. IIRC from my childhood, these sets included prehistoric animals, as well, though some included humans and dinosaurs in the same set, but they may have had sabre tooth cats and mammoth/mastodons, giant sloths and a few other ice age critters.