Hi
Thanks for sharing, and yes it does look abit like a railgun mounted to the bottom of your X350 Pro 
Looking forward to seeing some videos of how it turns out. at night as my only thought is that when you are higher up and there are no objects for the IR beams to reflect off you might not see anything, but I have never tried so dont know for sure!
Ah ha I’m doing something similar here, On the same quad Frame, but with QR X350 guts inside.
Yours maybe a bit ‘Overt’ as that, that cam, if not mistaken, is using the Highly Visible IR LEDs? usually 850nm wavelength, deep red visible glow on axis? (#Note: Colour cams are rubbish at IR wavelengths, a B/W cam setup works best).
The ring type IR LEDs are cheap and convenient, just way Too ‘Visible’
I work in the …cough… surveillance industry, my current test setup is using 4x IR power LED’s at 950nm (invisible on axis) each IR Power LED has 4x IR Chips inside, supposedly 5W, I have de-rated these to 4W for a total of 16W, all 4 in series pull 1.4A @5.6V and get hot.
The power LEDs are on Hex aluminium PCBs, then mounted on a heat sink, each take 2 LED’s, so 4 power LEDs in all. They are fitted with Optics, 2 Wide angle, 2 Spots.
As I will be wanting to see a few 100 metres, in total darkness, I’m using a Mil spec camera for the FPV video downlink, this camera can ‘See’ in light as low as 0.00003 lux. A puff on a cigarette would probably light up a person 80m away 
The only problem with this wonderful gear? I can’t afford to crash my quad, as the camera costs over twice what the quad does, so currently working on camera crash protection, just in case…
I’ll use a spare channel to toggle the Nav lights to IR, so you won’t see it.
This works better at fairly low altitude, any moonlight will light the ground terrain up, if there are distant light sources around also, that will give you bearing information. Tactically, getting to the target at a high altitude is beneficial, assuming some starlight, with less chance of being ‘heard’
This is an on going, but slow project due to cancer, and chemo makes you feel like crap, so it’s a bit stop-go.
The QR X350 option is only being used for the initial development, a Tarot Iron Man 650 CF frame and assorted goodies is winging it’s way to me now for the ‘proper’ version.
Hopefully, the heavier lift version will allow 2 x IR mil spec cams, one with a 4mm CS lens, one with a 100mm lens, switching between the two camera’s remotely, this will give a much longer stand-off distance for surveillance, probably out of hearing range also, so quite useful.
Oops, rambled a bit on my favourite subject, sneaky video stuff…
Will post some footage as soon as all the bugs are ironed out, initially, on the ground.
Steve