Somewhere on Enworld I had seen a houserule that boiled down to "If a minion is attacked and not killed, it is bloodied."
I've been thinking about abosrbing that one.
I put a post like that, but can't find were I put it. So here is was I am doing now that came from my post.
Tough Minion - The tough minion is a minion who has learned through combat experience or simple natural ability how to make it through a fight somewhat better than the rest of his kind, but still cannot be ranked among the best.
Tough Minion - Elite Minion
Humanoid or Undead XP Elite (twice normal minion)
Defenses +1 AC, +1 to any two other defense
Attacks +1
Hit Points 2 (Missed attacks never damage a tough minion, unless its bloodied.)
Tough Resolve [Con bonus] (immediate reaction, when hit by any attack; no action)
When a Tough minion is hit by an attack if the damage is less then its Tough Resovle mark the minion as bloodied with 1 hp left. Any damage taken after kills the minion. (note: con bonus = con mod + ½ level)
Desperate Strike (free action; encounter; recharge when bloodied)
When a tough minion hits with a standard attack, increase its damage by +3 normally listed.
This increases to +5 damage at 11st, and +9 damage at 21st.
This works great if you make 1-2 out of 4-5 of the Minions tough and don't tell the PC's till they hit one and don't kill it. But any way you do it, its pretty balanced, I think.