PvP Arena Event

[Evershifter]

This summer, I plan to run a small tournament for the players in our group.
Each player builds a party of three 8th level characters and fights to see who built the best. I'm thinking a double elimination style tournament, so everyone gets to fight at least twice.

Just looking for thoughts/suggestions on what can be done to improve the experience for everyone.
Suggestions for various arena locations/traps.
Houserules to keep things balanced.
Spells/items to disallow ahead of time.

[hogarth]

House rules:

Have some kind of limit on expendable items to prevent things like buying scrolls of Gate or whatnot.

Have some kind of policy on pets. Are purchased creatures allowed (e.g. warhorses and riding dogs)? If so, how many? What about pets from spells like Animate Dead or Planar Ally?

Have some kind of policy on pre-buffing. Can a spellcaster pre-cast any spells? Can PCs start with any items in their hands?

Have some kind of policy on hiding and/or running away. Can I hide for hours while my opponent's spells expire?

Have some kind of policy on resting between fights. Do the fighters get to regain all damage between fights? All spells (note that this heavily favours spellcasters)? What about sundered equipment?

Personally, I have experience with the (3.5E) Core Coliseum forum on the Wizards of the Coasts boards, so I'm biased towards the rules they use somewhat. Here's a link to their rules:
http://community.wizards.com/coco/wiki/Rules_of_Gladius_(3.5e)

As you can see, it's a huge list. To summarize:

They allow a fixed amount of money's worth of expendables for each fight. Expendables with a higher caster level than the PC's character level are not allowed (e.g. no 8th level PCs with scrolls of Wish).

They allow a certain number of purchased animals to accompany the PC. I'd probably restrict it to one horse/pony/dog in addition to any eidolons, animal companions, familiars or other class feature pets, but that's up to you.

They allow prebuffing of any spell or effect you want, but 1d6 hours pass before any fight. PCs can start with one item in each hand.

They only allow 10 turns' worth of delaying (i.e. any action that's trying to avoid the other PC).

They rule that any damage is healed between fights, but you only get to refresh spells every three fights. Refreshing spells every two fights is probably okay, but refreshing spells every fight really does favour spellcasters.

There's also some ideas and maps for arenas there:
http://community.wizards.com/coco/wiki/Rules_of_Gladius_(3.5e)/Maps_and_Lig hting
The Arena map is a good all-round choice, although it's probably too large for a tabletop game. The Temple map is smaller and has some interesting features (e.g. a lava pit!).