Oz, the Tb-3 bomber was done by Wyrmshadow in a good quality longer time ago and is available as download of Wyrmshadow´s WW 2 planes:
http://forums.civfanatics.com/showthread.php?t=222434 If you have downloaded SOE, this unit is included as R069 Russian TB-3.
But there is another until now not existing 4 engined bomber that could be done from the generic bomber of this thread and that could be of real importance for WW 2 scenarios:
The German Do-19 "Ural-bomber":
http://en.wikipedia.org/wiki/Do_19
It was built for the Luftwaffe's Ural bomber program under General Walther Wever. The RLM Technisch Amt issued a specification for a four-engine heavy bomber. But after Wever's death in an airplane crash in June 1936, Wever's successor, Albert Kesselring, canceled Germany's long-range bomber projects to concentrate on tactical bombers. If Wever wouldn´t have died in that aircraft crash, may be Germany would have had "B-17-like" bombers in early WW 2.