Competent UNIX admin? Let me submit that it's just not needed to be competent with UNIX: You just need some basic knowledge of the concept of a subnet, and it might help to know what a broadcast domain is.
Anyone who can configure a venerable WRT54GL with OpenWRT or Tomato or DD-WRT and isn't afraid of a 900MHz ISM-band Ubiquiti (or other) radio can do this.
It's just Ethernet frames that happen to encapsulate IP. No big deal.
I mean, FFS: A couple of years ago I built such a system. A wealthy customer was having a party, and was having circuit issues on the bonded T1s at his house (yep, really) and Really, Really wanted his Sonos system to be reliably online to stream music for his guests.
We sent his wife to the Verizon store, and she came back with an LTE Wifi hotspot. I set up a WRT54GL running Shibby's Tomato-USB as a wireless client put the LTE hotspot in a window where it had reasonable signal. We had another WRT54GL working as a wired client off of this (triple-NAT? so what), which in turn plugged into the Sonos mesh with some Cat5.
DHCP figured out the addressing automagically; all I needed to do was make sure that each WRT54GL was issuing a unique subnet so Linux's routing tables weren't confusing itself.
And....done. It was an ugly hack thrown together late on a Saturday with parts on-hand and it got the party going just fine.
Which is the same as, or perhaps slightly more complicated than, a ProxyHam setup.
Oh, and ProxyHam is easily traceable, too: I haven't actually had my hands on Ubiquiti's 900MHz gear, but their 2.4GHz 802.11N stuff has an excellent and honest spectrum analyzer built-in with the default firmware. I would be shocked and amazed if their 900MHz parts differed in this regard.
A $100 radio, some graph paper, a directional antenna, a working brain and some mobility is all you need to use to triangulate the "isolated" end of a ProxyHam/ProxyGambit connection that is actively being used down to at least the household that the signal emanates from.
Alternatively, any spectrum analyzer that covers whatever band it is that is used to backhaul to the user's location can be used to locate them fairly easily: You can try, but at the end of the day you can never hide while broadcasting with a radio -- especially since we've largely abandoned frequency-hopping spread-spectrum (which was actually rather hard to narrow down using traditional tools).