Those big Soviet bombers were truly extraordinary and awe inspiring (and make a terrific model as well - that's some work), but militarily they were quite useless. Far too big and cumbersome to have been of any real practicable use, not to mention too few of them to have run an effective strategic bombing campaign. They were slow, unmanoeuvrable, had a low ceiling and suffered from structural issues, all of which would have made them extremely vulnerable.
The big ANT-26 was actually begun construction, but it was abandoned in the mid 30s after years of work. Tupolev planned airline variants of the ANT-26 as well, which would have suited the design better than as a bomber.