7: A Compact, Secure Way to Mount a Nano
(modified 9/22/15)

I got a couple of these through Aliexpress. Without wires coming out the edges this thing is less than 1.5" wide.

Each Arduino pin is brought out to a screw-down connector. Screw the patch wires down and the whole thing is much more rugged than using a no-solder breadboard. The unit came in pieces -- 60 solder joints to complete it. Yuck. Testing them all was a trial.

Another mounting trick I'm interested in: use a 40-pin ZIF (zero insertion force) connector.

I'm not sure if this will work -- is it wide enough? But if the Nano fits with width to spare then you could put the Nano at one end and also clamp jumper wires out to sensors, etc. NOTE: Doesn't work!