what I would like to see ....

[oric_dan]

if you have adequate link budget, the reduced RSSI doesn't really matter, and so resolving it, while desirable, is little more than icing on the cake.

Yeah, my experience with the RFM69 radio is that I have more than enough RSSI to spare where I use it. You'll notice my post on the other thread, where I was getting RSSI about -80 dBm [still approx 20 dB above rcvr threshold] across 500' distance from inside my car to inside a metal-frame bldg. That's phenomenal to me.
https://lowpowerlab.com/forum/index.php/topic,1494.0.html

Inside the house, I can use even minimal Tx power [~5 dBm] and have good RSSI at 30' distance, so all in all, the problem you've been finding might only be an issue for extreme cases. But I think we have good perspective on this now, something to cite. And like I mentioned previously, if an uncommitted 2x8 header where laidout on a Moteino-Gateway pcb, then people could play all they like with such setups. Probably better that than trying to build it all in from the get-go.

I might actually try it down the road, using both radios on my RF-Node pcb shown earlier, and then report back. Right now, I just got my robot tank RoBurt going 3 days ago [at long last after a lot of work], using Moteino radios for comms from robot to PC, so I'm hot to carry on there. There is currently over 60-pages of code, so my head is spinning already, DUH.

[WhiteHare]

Closing the loop, yesterday I soldered the ESP8266 parts to a PCB (the previous version looked like a Dupont wire orgy and also used a different 3.3v voltage regulator), and then ran RSSI measurements using a narrower bandwidth and my now more evolved methods for capturing RSSI noise.

The good news is that with a regular Moteino R4 with a wire antenna, and with the improved ESP8266 just a couple inches from the antenna, there was no meaningful difference in the amount of RSSI noise detected.

For those interested in the details of the comparison, see:
http://pastebin.com/vC5bx0fs
and
http://pastebin.com/g2tqNi3W

[Edit1: the above two measurements were taken with the Moteino R4 and ESP8266 (an ESP13) on separate circuits, each with their own power supplies run from batteries.  The good news is that powering them both from the ESP8266's power supply (an LM1117T-3.3v powered by four AA batteries), yields the same level of RSSI noise as when the R4 and ESP13 were not directly connected:  http://pastebin.com/sCmXAhwg]

[Edit2: OK, I just connected the Rx and Tx of the ESP13 to the Moteino R4, remeasured, and also no meaningful change in RSSI noise: average RSSI noise measured over 1000 samples at this same narrow bandwidth is -118.79.  BTW, since all this is just an experiment, I am using Dupont wires to connect the ESP13 to the R4.  ]