would it make any sence to install a couple of LEDs on the IDE cables to know whether the empeg is accessing it's Hard Drives

IMO, no. What would you gain from it? Das Blinkenlights?

Of course, it should be easly possible, and you can do what you want, but I can't see any use for it. Personally, I keep the hard drive icon(s) turned off, as I couldn't care less when it's accessing the drive.