Love to hear those thoughts.
Unfortunately, it doesn't translate readily to 3E, since I'm working with 2E-style initiative.
The basic initiative system is this: At the start of the round, you declare what you're doing. (DM declares first, then players going clockwise, just to keep things simple.) Then everybody rolls 1d6 for initiative, and the DM starts counting down from 6. When the DM calls your initiative count, you resolve your declared actions. If two people act on the same initiative count, their actions happen simultaneously*.
Originally I had separate rules for aborting your declared action and readying an action, but after reading this thread and pondering for a bit, I decided it made more sense to combine the two. The way it works now, when your turn comes around, you can either resolve your standard action or "hold the action." If you hold the action, you don't use the standard action right then, but you reserve the option to jump back in and resolve that action at any point until the end of the round. (You can't hold your move action. Move actions are use-it-or-lose-it.)
If the round ends and you still haven't executed your held action, you can hold it over to the next round. If you do this, you must declare the same standard action again, but your initiative is automatically increased to 6.
So, taking the "gladiator problem," let's say your gladiators are called... oh... Roy and Thog, just to pick two names out of the air.

They start 40 feet apart. Each of them declares that he will move, then attack. They roll initiative; Roy gets 4 and Thog gets 2.
Roy moves 30 feet (they are now 10 feet apart). He's too far away to attack Thog yet, so he holds his attack action.
Thog could move up, but then Roy would jump in and get the first shot. Being smarter than he looks, Thog declines to use his declared move, and holds
his attack action. The round ends.
Next round, both combatants have held actions. If they keep those actions, they get to go on initiative 6. Both of them do so; once again, they will move, then attack. Since they have the same initiative, they act simultaneously. They move forward until they're in melee range, and then both attack at the same moment. At this point, neither has any reason to continue holding--they'd just be giving the other guy the first hit.
[size=-2]*This will obviously require some judgement calls from the DM. 2E-style initiative does not lend itself to the kind of rigid, tightly defined rules WotC favors.[/size]