The Zombie Dragon Template from Draconomicon halves the Dragon's Natural armor, applies -2 Dex and -6 Charisma, but they get to keep their breath weapon.
I looked in Draconomicon which has the Chaos Dragon which allows the Dragon to make a Cone of Confusion: Will Save or be Confused for 1d6 rounds+Age Category. That kind of save or die is very nice. The Ethereal Dragon Force breath is very nice, hurts incorporeal just fine and little resistance. Oceanus Dragon is even nicer. Grating a breath weapon to save or be dazed for 1d6+age Category Rounds. Pyroclastic dragon is even nicer. Disintegrating line, save vs. fort or crumble to ash!! Straight up save or die!! Shadow Dragon is very nice too, the affected creatures gain negative levels.
For games that allow Pathfinder, I found the following Nice Monsters that should make good uses for Planar Binding:http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/wendigohttp://www.d20pfsrd.com/bestiary/monster-listings/outsiders/demon/marilithhttp://www.d20pfsrd.com/bestiary/monster-listings/outsiders/demon/demon-shemhazianhttp://www.d20pfsrd.com/bestiary/monster-listings/outsiders/devil/horned
The Wendigo seems to be the king of mobility and damage, dealing 4d6 extra cold damage off of its 3 attacks. Assuming you don't need the 120 ft speed, the Shemhazian seems to get the most damage per attack while the Marilith has the greatest potential since she has 6 arms + Tail so if you had magical weapons it would eventually outdamage the Shemhazian.
As far as tactics go, I can imagine a team of Shadow Dragons and Pyroclastic dragons working together. The Shadow Dragons will all breathe to reduce the saves of the affected creatures while the Pyroclastic dragons will breathe on the foes to cause them to die. That being said the dragons will be vulnerable during the inbetween rounds and can get pummelled very easily. Perhaps 2 Wendigos to be frontline fighters and defenders to intercept.
So since my DM has limited me to 6 corpses from outsiders gained from Planar Binding, I am thinking of:
2 Zombie Dragon Pyroclastic Dragons
2 Zombie Dragon Shadow Dragons
2 Skeletal Wendigos
Now that being said, the dragons are a liability in that they only get a standard or move action per round which can really mess them up. Any ideas on how to improve this? I can only think of a Belt of Battle, but the problem with that is that it takes a mental action to activate and decide how many charges to use, and I'm not sure if I can argue that a Mindless Undead can do that.
Secondly, they really need some Charisma, I am thinking giving them +6 cloaks of Charisma, but that can be expensive, but it sure helps their DCs which are critical in this exercise.
Any help is appreciated.