what are your plans/uses for the optics? if your gonna set on an elevated tck platform at night, go with night vision. if your wanting to walk around with them, get a cheap thermal handheld for located hot spots in walls of short range visuals in the woods.
here is atn's website with some prices for scopes.
http://www.atncorp.com/thermal-weapon-sights your talkin a lot of money to drop for thermal imaging. i dought you will find military grade but this is as close as possible. try a flir unit too.