[PsiSoldier]

Hrrrm What about one of the nations with Song spells that reinvigorate? with Clockwork horrors just set to guard commander while the commander casts the reinvig song.. Of course I'm not sure how fatigue those spells actually get rid of and also there are the scripting limitations with Dom3 so your mage would start casting other things once your limit of scripted spells was used up... And the oportunity cost of spells your commander could be casting instead. And the fact that you have to wait for the enemy to come to you...

That option sucks I think.. But its about the only way I can think of to keep them going for a little while longer..