Looks like the beginning of a suicide spec. Nothing wrong with that combo, just understand its "limitations" and its use.
This being said, since the 2.3 patch and our free respec...I have now been to the top of the mountain of the suicide spec...and it is good :)
This being said, yes I do have both EF and SF. I haven't really "measured" if they stack, but I do notice that both can proc at the same time...its just that I'm usually spamming macro's to much to notice that if it actually did reduce the MP cost. I'm guessing, but I think it does stack.
I do want to mention something, since I see your talents going down the suicide path, if your not already aware of it.
Suicide specs are typically PvP specs, and are best suited for BG or "large team" PvP situations. The method of operation for these specs is based on the fact that your goal is to take down as many ppl as you can, BEFORE you die. Due to the lack of healing skills, death isn't a matter IF but WHEN. Suicide specs obviously capitalize on flexibility of dps range, which is more "common" in BG setting, but is completely useless in PvE settings.
Obviously while soloing, you can only melee OR cast...not both. So when your underfire and have a mob in your face, trying to squeeze a "weak" LB out with slower casting time is not worth the dmg you would have had if you had just kept meleeing it (assuming your enh heavy). Because of this fact, it basically means while lvling, your only using HALF of your specs potential.
Also, considering that Enh and Elem spec require to completely different stats to compliment the abilities. Obviously Elem looks for caster type stats, and Enh looks for Melee stats. Due to the fact that gear has either caster OR melee, you are still forced to focus on one aspect of dps, leaving the other "gimped". While 2.3 does offer more caster potential for Enh specs, the rules still due apply, as a Enh overall dps is still focused on melee dmg...not casts.
So, if your going Enh/elem your gearing is going to tend to melee, which means the base spell crit rate (no buffs) is going to be something like 5% (well mine is @ lv 70). Not hard to see that your not going have the clearcasting pop much, and hardly something reliable.
Vice versa, if your a elem/enh...sure your spell crit might be HIGH, but that means your melee crit is going to be low...so your not going to see SF much.
This pretty much shoe horns suicide specs into JUST BG PvP. So why might you ask, would I actually be a suicide spec myself, despite the obvious downsides?
Well, first of all...I'm a 70, so I'm not lvling grinding anymore (until the exp.):). 2ndly, due to speicific gear setups...I've "offset" some of the problems I mentioned that are typical with a suicide spec...I didn't completely CURE the downsides, but I have other factors that don't make me RELY on small % procs. For example, the DM trink that ups crit rate for BOTH spell AND melee when it doesn't crit (kinda makes having a lower crit rate work in my favor...sorta).
Course, this is from the perspective of a lv 70, which because of gearing @ lower lvls and lvling in general, it makes this type of game play and spec almost unrealistic...unless you DO plan on using this mostly for BG PvP play. Keep this in mind.