Thank you all for the replies, and I thought I'd just take a moment to let you all know how it went.
I used an Ancient White, and gave her the feats of Hover, Snatch, Wingover and Flyby Attack (amongst other). Since I also have a large party I rarely set up a situation where they are fighting a single monster, alone. It took me days of leafing through various books looking for inspiration (and something that would work, logically). I finally settled on a wing of classic Gargoyles ... except I made them "Ice Gargoyles", which were mostly a cosmetic variation (i.e. they appeared ice-like rather than stone), although I did give them the 'cold' subtype.
I placed the dragon's lair in the great hall and throne room of an ancient frost giant lair (so everything was nice and large), but one that had been partially swallowed into the earth so that the rest of it was collapsed and the only enterence was through an opening 200' down a 1000' rift in the icecap. The enterence led into the throneroom which is where the gargoyles kept (amongst a collection of ice sculptures). The second room was the dragon's lair, and was seperated from the main room by a wall of ice.
Coincidentally ... *ahem* ...

The most strategic, defenseable place to camp out and still have a view of the rift was exactly 200' above the second room.
To help get the picture, perhaps a better description of the party is in order ... [sblock]
My party is much larger than usual (eight players, plus several cohorts). It is also more combat oriented with only one pure arcane caster (although several have from one to three levels).
Boceefus: 13th level Cleric/Wizard/Astrologer (a prestige class in the service of the Goddess of the Night Sky and has domains in divination, travel and magic). 'Bo' has two cohorts;
Glynnis: a Cleric/Wizard like himself who normally does most of the party's research and bookwork, but accompanied the group for this mission. And
Ambro: An Ogre Barbarian which Boceefus "converted" with the help of a Helm of Opposite Alignment.
Snjolfur Vimunder 13th level Psychic Warrior and one of two "tanks" in my group.
Tobias 12th level Rogue/Fighter and one of two ranged weapon specialists in the party. Tobias has a Cohort
Link a fighter whose main purpose is to fight alongside Toby as his "bodyguard". Is very adept in using the Spiked Chain.
Dashanial 11th level gnome Rogue/Illusionist. Where Toby is more of a combat Rogue, "Dash" is the party's main lockpick, trapfinder, treasure filcher and gadfly.
Ha'kim Silverleaf 10th level elf Ranger/Wizard. The other ranged specialist. Is working toward the Arcane Archer prestige class.
Phanta Schtick (yes, that's her name lol). 10th level Wizard.
Amras Dolgnskjald 9th level Dwarven Psion/Fighter. Ends up more like a psychic warrior. The other tank, and if I havy any probably the most "munchkinned" character.
Barilla 8th level cleric of the Goddess of Mystery and Secrets.
[/sblock]
The party decided to spend one day scrying, and would prepare combat spells for the next day. They did a great job with spells, and physically scouting out before hand. One member was able to fly invisibly into the lair, with detect magics and detect evil. Unfortunately (for him) he did not get close enough to the wall of ice to sense the evil and the magics beyond it. Also unfortunately, the dragon could smell them, and planned a pre-emptive strike.
That night, I had the gargoyles fly out and swarm around them while sleeping. Two rounds later, the dragon (who had been burrowing up from her lair) burst out underneath where the party had been camped. As the party mopped up the gargoyles (a little quicker than I expected), the dragon burst forth and used snatch to pick up the nearest human, which happened to be the wizard cohort Glynnis, and flew off back toward the rift.
The cleric (Boceefus) was close enough that I gave him an "attack of opportunity" to grab on to Glynnis and go along for the ride. Since he already had a fly spell active, he was able to keep up for a while but the dragon had much greater fly speed and Bo wasn't able to maintain hold with a strength check.
Boceefus flew off after the dragon, but watched helplessly from a distance as the dragon dropped Glynnis into the rift. Boceefus immediately teleported himself into the rift, near the base.
In the meantime, the rest of the party mopped up the gargoyles (much quicker than I expected, I grant) and used a combination of dimension door and teleport to get themselves into enterance of the dragon's lair. Immediately I described the sound of Glynnis screaming as she was dropped from the dragon's maw.
Snjolfur was the first to react, and leapt from the mouth of the cave ... successfully made a luck roll (for good measure), an attack roll and a grapple check to grab Glynnis and hold on as she plummetted down the crevasse. He then prepared to open a dimension door, to put them both back on the cave floor ... but the real fun I had was describing to the 10 strength Boceefus that he now not only had the lithe Glynnis plummeting toward him, but the hulking burly fighter as well! LOL
Meanwhile, the dragon flew back toward the battle site and was surprised/disappointed to find the battle over. Fearing for her home and treasure horde, she immediately made for the cave enterance. Hovering outside the enterance, she used her breath weapon on the party but to little effect (they had done well preparing themselves against cold based attacks).
The party fell further back into the cave, and the dragon took the bait ... pursuing them deeper. Several rounds of combat ensued and she found herself doing more damage to the heroes than she was taking ... but the tide turning factor was the healing that the party got from its clerics. Realizing she couldn't win the battle like this, the dragon retreated up to the surface and back down through the hole she burrowed, to protect her treasure horde and to recover.
Unfortunately, this time the party searched more thoroughly and were able to detect both evil and magic behind the icewall. Subtly bursting their way through with a fireball, the party renewed the battle. The dragon attempted a parley, but the party would have none of it and slew the dragon as it tried to escape through the hole it had burrowed through the cieling.
All in all, several members of the party were brought low (including the two tanks) but I didn't actually take anyone out. I had counted on the battle staying outside much longer, and several being dropped into the rift. None the less, it's certainly possible to have a great and memorable battle without any character deaths, and I did just take down four party members a few months ago.
