Todo list for the weekend 3 nights from now...
1: Look into porting csdr to FreeBSD.
2: Bench mark rtl_fm, csdr, and GNU Radio for analog demodulation.
Sadly looks like the end result will be going with GNU Radio as something that supports piping, does analog demodulation, and is a command line tool is not really something that exists in any real notable or useful manner.
The only real one I've found is csdr, which appears to have some issues from the initial look.