The Tupolev design bureau had its own project for a long-range bomber in WW2, the Tupolev ANT-64. Pictures of the ANT-64 (below) are available from Туполев Ту-64 (Ту-10).
I've posted a drawing of the Douglas XB-31 (Model 332F) bomber derivative of the DC-4 and the Douglas Model 423 intercontinental bomber (the one with the bug-eye cockpit) to give you an idea of what the XB-31 would have looked like. As Alan Griffith has noted, the true XB-31 is the Model 332F, not the Model 423, because the Model 423 was conceived in late 1941, long after the XB-30 and XB-31 lost out to the XB-29 and XB-32 in the R40-B competition.