[Baalz]

I love Umbrals. Send 2 umbrals per mage, and cast earth power/iron warriors/iron warriors (then whatever you want). With 20 protection, ethereal, good hp and life drain they're ridiculously effective for a cost of 2 death gems.

Ubrals + Gift of Reason is also pretty darn good. Stealthy, ethereal, good HP, life drain, 0 encumberance (slap black plate on them with no fear). 2d+20n for a pretty reasonable SC chasis if you can swing the nature.

Also, with those bad *** earth mages I find its usually more effective to go with buffs/de-buffs than damage dealing spells. Just watch how effective your light and medium infantry is with summon earth power/strength of giants/legion of steel/destruction/destruction.