It is said in some sites (including Wikipedia) that based on some cross-references the Bakuman and Death Note, the author, Tsugumi Ohba, is actually a pen name, and his real name is Hiroshi Gamo, another 50-year-old mangaka that was some kind of one-hit-wonder in the 90's.
I couldn't find any reliable source for verifying this, does someone know if this is true from some source (interviews, press...)?