I am not sure if this is covered in any other material, or covered in any pre-SR4 material, but would it be possible for thermal dampening to have a power equivalent? How much would it cost, assuming it would be able to be toggled on and off?

Don't see why not. Simply use the same rules as the ones for armour modifications in Canon Companion, each level adds +1 to Perception Tests to notice the target using thermographic vision, and have it cost .25 power points per level. Seems like a fairly reasonable price since most per level powers cost that like the Cloak one.

i was trying to figure out why this idea sounded familiar. then i realized, oh yeah! i wrote it up!

Its essentially a limited form of the camoflague spell and a limited form of improved ability adept power.