Hi Mark,
Welcome aboard! In the first edition of the campaign (Best tank that never was - #177 by barkingdigger) I built that M48 combo! It’s a real beast - I don’t know if it would be any good at AA, but it would make mincemeat of ground positions if used in the support role… 
That other tank in your post looks interesting - I wonder what 1:35 kit would form the chassis for a kit-bash? (A slippery slope for me, as I already have too many build ideas wrestling for space in my head.)