A majority of this does seem to exist.  The only area I'm aware of that
is lacking in ruby right now is the Geographic libraries (which I would
be interested in if anyone knows of some).  Aside from that, I think
that a little work could be put into a chosen set of libraries to make
them work together more easily, and you'd have a pretty powerful set of
tools.  Integrating anything written in pure ruby wouldn't be hard most
of the time since ruby is pretty lax about typing.

A fairly powerful command line environment could be built with a few
extensions to ruby's irb.
  .adam