Specifically, with Quagmirran's Eye, but there are other items with an invisible cooldown on their proc. The main reason I'm asking is because I've noticed that Counterspell can proc the ability and doesn't use the global cooldown... so on fights where I have the spare mana and can just add it in whenever the cooldown is up...

I'd actually thought a decent bit about this; it should be possible to track your buff gain messages and when you see a buff that pertains to a given trinket, start the "hidden cooldown" timer for that trinket; on the character screen you could have a cooldown graphic and everything.

Something less advanced, but no less functional, is to download my mod SpellWatch (soon to be hosted in the wowace svn!) and set up a timer for a self-buff with the right name and duration.

The problem with that is that you would have to know the length of the "hidden cooldown".

Well yes, but you would anyway for any other solution. It's not like we have a way of absolutely determining the hidden cooldown on anything; we can only note from combat logs that "it's never procced sooner than x seconds after a proc goes off" and make reasonable guesses.

Well the addon itself might as well automatically figure this out on its own as well.

Certainly, especially if it were just a "rough and simple" mod that someone wrote mostly for personal use, you could just assume 3x duration (Duration is gettable from the tooltip, yes?) for anything you don't have data for, and mark it in some way (different color?) as potentially unreliable.

And then the mod could be updated periodically as the cooldowns are confirmed.

Because whenever anyone new downloads it, or you reinstall wow, you have to begin the whole data-gathering process again. Which is fine if the data could vary from person to person, but it can't.

You could use that to support unknown cooldowns, but that's a lot of overhead to carry around for stuff "we" (the WoW community) already know.

if i know the cooldown what would i need the addon for then? :X
simply add a custom warning in your spellalert addon of choice, you can even create a custom bar in bigwigs or whatever

For me (not that I have a use for this), having a symbol that shows me when the cooldown is *up* rather than when it's not is far more useful. Hence the issue with bars. And one-time warnings, if I don't see them, I may lose track of whether it's up or whether I missed it.

This is why ghost timers are so useful for locks in dotimer.

If a mod like described by op Or a mod like Spellwatch (tried the old version, very buggy now) exists today, I would very much like to know =)

Syncing mage cooldowns with dying curse is huge :F

A) use the whats that mod thread.

and B) Procodile - Addons - Curse

There's also an addon called Bang!Proctologist that shows the internal cooldowns of just about everything. It costs $2 bucks though, which could be considered crazy.

Bang! Proc-tologist 3.09.10 - Info Tracking - World of Warcraft Mods, Addons, and More!