If you lot can be patient for up to a couple of months, I may have a solution for you. I'm in negotiations with an electronics company to produce replacement power supplies for ex Soviet Gen 1+ NV gear.
The issue is that, as issued, they have a pretty simple bomb-proof transformer attached either to the unit or part of the rig you wear the unit on. The type I'm hoping to be able to adapt to airsoft are designed to be worn head mounted while driving. This fat transformer acts as a counterweight on the back of a padded canvas helmet. They have a lead which plugs into a socket for 12V or 24V power.
There's no issue with power: they even run off a 9V PP3. The problem is with the transformer because when in operation it makes a high pitched whine - not that loud, but loud enough to give you away in a sneaking around scenario. However, the company I'm talking to have agreed to have their tech team look at designing a modern electronic replacement for the transformer which will operate silently and run off any of these common airsoft voltages 7.4V, 8.4V, 9.6V (so batteries can be interchanged with existing AEG ones). The bloke said he will probably have a proposal by the end of next week.
The reason this needs a proper bunch of boffins to do is that the stock transformer output is 15-19.5KV, although research suggests that the tubes in the eye pieces will work at 10KV (which is something I will soon discover as I have a 10KV unit made from a bunch of smaller quieter transformers in the post from the USA - although I can't afford to buy the NV goggles for a month). Anyway I'm sure you all realise that, even though the current will be something like 3.9mA, well below the 52mA generally agreed as the minimum necessary to stop a human heart during ordinary skin to conductor contact, double figure thousands of volts attached to our heads would make for some pretty funny mong-ons if it went wrong. Of course, if we didn't get a taser-like shock to the head, dodgy connections and/or apparatus could still create bright blue, loud, arc flashes, which would give our positions away
What makes these things so good for airsoft is that they are designed specifically to maximise the view at driving-relevant distances and also a wider angle than standard NVG or weapon mount scopes. What's the point of £6-7-800 NV that can image stuff crisply at 300m when we can't shoot that far? They work by maximising very low light levels, some amount of UV, and IR. So yes, they will work in indoor complete darkness with an IR illumination source. Depending on supply, they sometimes come with 2 or 4 massive headlamp IR filters, but the ones I'm looking at do not have a built in IR emitter.
Not to worry! I have found a cheap source of Cree IR LED's and another for a limited number of IR lasers. The thing to bear in mind about these things is that they are made to withstand war. If you manage to bust one by 'blunt force trauma', you'll have a lot bigger problems than fcuked up NVG, ie a caved in head. I'm planning to create mesh or polycarbonate lens covers also and, depending on how the 1st one melds with my eyepro, possibly some sort of custom mesh mask...
How much then? Depending on a number of variables, I'm hoping for a max price of £300, quite possibly cheaper.