Isn't there anywhere you can glue a chipset heatsink and maybe a fan on the circuit board? I guess touching any large pieces of silicon would help you deduce which component is overheating, probably voiding your RMA options in the process
.
Also on the subject of NAS, anyone see
This on el Reg? Not strictly just NAS, but I can think of a few nice uses for it. Pity it doesn't support audio/video devices (yet).