yes, the Tu-2 is it....
They actually built a removable tray that filled up the bomb bay....in this tray were 88 machine guns, all set to fire at an angle forward and down. The plan was to use this against enemy troop concentrations. They actually flew this beast, and found only two problems--the firing time was so short that the pilot really only got in one pass before it was time to reload. The second problem, and the bigger problem of the two, was that it was very time-consuming and difficult to reload all of the guns with fresh drum mags while in flight. So the idea was killed off. Imagine, though, a firing rate of just under 80,000 rounds per minute....here is a link with a couple of photos of the design. All told, this aircraft carried 93 guns installed in firing positions at the same time. Unbelievable....
www.militaryphotos.net/.../showthread.php