Most unconventional tank designs of Cold war list.
1. 2 cannon tank with 2 man crew, 1977, Morozov design bureau. Project 490
btvt.info/7english/490_2gun_eng.htm
2. 4 track tank of the beginning of 80s, extraordinary protection, crew of 2 placed at the rear of the tank, Morozov design bureau.
btvt.info/7english/obj...21_vek.htm
3. This object 490A one may look rather conventional design, but it had one very unconventional feature – it’s rounds charges had to shift its shape before loading (variable form charge).
btvt.info/7english/490A_eng.htm
The #1 was criticized, number 2 was designed up to USSR collapse, only turret built, #3 – 2 tanks were built, only one hull survived to our days.
Maybe some common features like vehicles mentioned in Honeycutt’s – History of the American Main Battle Tank Vol. 2 (Associated Engineers Inc 4-track tank and so on) but not a completely unconventional designs.
Maybe somebody can add some US unusual projects, but I can hardly find something like the above mentioned.