Hi Obsessed,
From the MTN page for the S2+ host, it specifies that you will need a 16mm MCPCB (Metal Core Printed Circuit Board - the board that the LED directly sits on), and a 17mm Driver (the board with the electronic components that controls power to the LED).
You said that you want a IR LED in the 850nm wavelength, but I am only finding this one (
http://www.mtnelectronics.com/index.php?route=product/product&path=60_105&product_id=371) which is rated for 940-950nm - is that a deal breaker? I'm assuming you'll be picking up the IR with night vision or something.
Also, what level of involvement are you looking for here? Are you looking to 100% DIY, including product selection, soldering, etc., or are you looking for someone to make this for you? If you're DIY, I could point you in the right direction. If you're looking for someone to build it, I am in the startup phase of my flashlight company and I could do all the work for you if you basically just want an IR wavelength (940-950nm) S2+. Let me know and we can discuss details if you're interested.
Matt