I've updated my IceCap addon (WoWInterface download link). While primarily for Frost, it may be of some use to other specs, and I'm open to suggestions for improving it for them.
My mage's terrible gear aside, it calculates the ratings you need to reach various caps for boss-level targets.
Crit: Point at which spells will always crit with Shatter active
Haste: Point at which instant spells hit the GCD minimum during Icy Veins
It uses your current gear and automatically factors in race, professions, etc. All you need to do is specify which buffs you expect to have during your raids (and note that the list of buffs will update with you as you level).