I found a suitable replacement for JIM's CooldownPulse that works with WotLK. You can grab it here:
Doom_CooldownPulse
Of course, CooldownPulse isn't complete without a notice sound. Here's the one I prefer the most:
http://forums.blackravendragoons.com/filelib/2/lubdub.wav
Just download the WAV file and place it inside your Doom_CooldownPulse directory. In case you're wondering, the effect was ripped from Doom 2 and consists of the Revenant's primary attack sound: firing rockets.