FLIRs: I have some experience in this area. They are great when you are stationary or have a VERY expensive unit. I'm talking $10g's + for a single unit if you want to have something "worth it" for when moving. The technology is out there, it's just not practical or affordable for (most) civillians to have it. Most of the cheaper units will not yield the results that you will need. Maybe someday, but not now anyway.