morganw's advice seems sound. But all this fuss may be for nothing if my experience is any indicator:
1) use needle-nose pliers to squeeze off spring-loaded plastic tabs
2) apply smallish blade screwdriver between HSF and outside edge of motherboard
3) a slow gentle twist of the blade: a wee POP... the above picture shows the result.
There is no epoxy. It looks like the TIM used by Intel & others on their stock HS. On mine, you can see that it did not really melt. I think the highest temp I saw on the CPU was low 60s C during stress testing.
So. The HS removal seems perfectly safe -- the above operation took 2 minutes. And yes, I think a good chunky NB HS or similar would actually work fine -- with an "L" (low speed) 40 or 50mm fan on it if necessary.
There are lots of such fans rated 20-25 dBA; I've heard a couple recently that are not at all objectionable. Because they are so small, even though the RPM might be 4000 (which would mean a scream for a 80mm) the actual blade edge velocity is low, so they don't even whine. (I may have to listen to more lower speed small fans -- and maybe change my tune about the suitability of wee fans...
an ASIDE: Perhaps you can see -- on the CPU die are the words "HEATSINK/FAN REQUIRED" -- suggesting the thing could be sold or made available w/o a HS?