In this version, I removed the darlington detector and added a emitter follower(Q3) to bias Q1 and act as a reflex detector. With this arrangement the circuit works best with a supply voltage from one to two volts or so. I used three diode drops in series to achieve this. You could also use a LED. It has extremely smooth regeneration. The selectivity is excellent.
Again I got it to work with a wide range of values, so it should be easy to reproduce. I hope someone builds this and gives me their opinion on performance.
Schematic (revised 07/01/2015)