Ratte dimension in 1/56 would be length 62.5 cm, width 25 cm and height 19.6 cm. It's a whopper to be sure but not astronomically far out there. Consider 4X the up-and-coming-soon Spartan 28mm scale gunship at 57x34x13cm.
Don't see either of those as gaming vehicles as such, more as terrain features and/or collector's item type display minis.