GnuRadio as Antenna Analyzer and SWR meter

This may be outside of the scope of what GnuRadio is trying to
accomplish and complementary hardware would need to exist, but it would
be great if GnuRadio had modules to build a software defined antenna
analyzer for impedance matching as well as a software defined SWR meter.
Of course it currently has all the various spectrum analyzers and
GnuRadio could easily control something like an external antenna tuner,
but it would be great if (with the complementary hardware) GnuRadio
could automatically measure wave reflection and match impedance and for
its sources and sinks.