Jezz you should of seen the very large model in a display case, It was a super large gun called DORA, In 1/35 scale by Soar Art premium edition sprue brothers models metal.
There is 2,500 parts and 2m long. the gun sits on two train tracks, the bloke who built it put a few other bits with it a Panzer IV which looks very tiny, going to see if I can get a photo of it next time I am in Frontline. Oh kit cost $900

not something that I would buy but jezz it was a very nice model. in a very large display case. yes!