sunnywa is right: why would you fly without them??
Civvy NVG ops is NOT A NEW THING guys. There are well established methodologies, training courses, and cockpit mods. One company in the US (ASU o Boise ID) has done more than 280 cockpits!!! And contrary to Shy Torque above: modern glass cockpits are amongst the easiest to modify. There is an international standard that formed the basis for many of the countries already using them - SC-196 created the DO268 and DO275.
Swiss: 25 plus years, US: 15 plus years, Sweden/Norway: 7 plus years and now mandatory, NZ: five plus years and used by every single govt contracted night helo, Aus 2 years and used in every state. No need to re-invent the wheel, though I am sure it will be tried.
White external lighting does not need to be "compatible". Dont get conned by the salesmen. It needs to be considered in direction (that it does not shine into the cockpit or stop the rear seaters viewing outside) but compatible? No.
As I had said earlier - the use of white external lighting when landing so fundamentally alters the landing environment that alot of the fears of the military guys are just not realistic. White light provides ample peripheral vision, enables the NVG image to be very clear near the ground (and on finals when the recce is important) even on very dark nights.
For you UK gents, I suggest a quick trip to a scandinavian operator as a study tour will bring you up to speed with how different it is to our old military days. Banning NVG single pilot plus crewman and rapid response is very supportable when doing tac low level no white light ops, but this proposition is unsupportable for non tac white light situations. 128 subject matter experts have already gone through the issues on the international level and produced the standards. They have all gone slowly and now proven them over many many years.
All you have to do is open your eyes to other operations. It is all done for you.
When we tackled illumination levels as a limiter we realised that it is an outdated military concept, not at all applicable in areas of cultural lighting, and less and less an issue with Omnibus IV and above. We chose visibility. Australian and Kiwi rules state that the terrain (not light sources) must be visible 5000m ahead, or climb to LSALT. Note that there is no cruise flight below 500ft allowed on NVG. This vis tool enables us to consider atmospheric obscurants as well as illumination and cultural areas in one go. Norway has recently reduced the vis to 3000m and I would support that once a system is mature (say more than 5 or so years of widespread use).
To finish where we started: why fly without them?