There will be a B3 manned heavy bomber.

The mission is not going away.

The big question is will the United States be able to build a bomber
that is a big enough improvement on the B2 to justify the development
before we run out of heavy bombers?

I think the answer is yes.

The big improvement of the B3 on the B2 is going to be the use of
woven nanotube construction in place of carbon fiber. It will be
larger, stronger and no heavier.

The crew expands to four. They take turns flying to and from the
battlefield and while on station one crewmember flies the bomber while
the other three operate sensors and UAVs.

The first B3s should enter service in the early 2020s. At a low level
of production they be able to take over as the primary heavy bomber in
2037 when the B52s and B1s are falling apart.

http://www.globalsecurity.org/milita...rcraft/b-3.htm

-HJC