On Mon, 13 Oct 2014 08:38:23 -0700, Jim Thompson
wrote:

...snip....

This is one of those "I wouldn't do it this way", but I'm looking into
it at the insistence of the client.

...Jim Thompson

whew! but still, will have your name on it when finished.

However, I just confirmed that using a rod that is 5mm diameter by 1cm
long and the permeability changes from 2000 down to 1000 you only get
about 0.3% change in inductance. [remember I said a function of aspect
ratio?] which means *if* you tune the inductor, it will stay pretty much
in tune. At least for a Q of 100 and that should be good enough for
peaking the signal AND getting 1kHz through on a 100kHz carrier. [more
possible but allow some sloppiness] and 1kHz sidebands means at least
2kb/s. and that means at least 200+ Full Duplex so you're done.

The answer is yes it can be done that way.