Looking at 1/35 T28 to build as 1/72. Be mobile shore defense 8" gun. Top accommodates two Sherman turrets 75 or 76mm and two spots for M3 Lee or M5 Stuart 37mm turrets.
Such a deal :D
See attached.
Set in the pre-American surrender world of THE MAN IN THE HIGH CASTLE, a boondoggle at Aberdeen Proving Ground. The prototype was so big, it couldn't be moved far from the base and wound up being useless 'protecting' the upper reaches of the Chesapeake Bay.
Grid 17 / C-D below
(https://i.ebayimg.com/images/g/8mAAAOSwrF5kSwcm/s-l1600.jpg)
Find a decent 3D print or kit for two donor M8 turrets, the 75mm howitzers being added for close-protection smoke and HE.
https://www.thingiverse.com/thing:5887506 (https://www.thingiverse.com/thing:5887506)
https://www.ebay.com/itm/266020655890 (https://www.ebay.com/itm/266020655890)