Here's a summary of the rules so far:
FORCES
This is a multi-player battle, involving two Armies each made up of three independent ‘Forces’. Each Force is 2500 points and selected using the min/max rules for 2000 point armies.
The Good Army (High Elves and Empire) are the defenders. The Evil Army (Chaos and Dark Elves) are the Attackers.
The following rules relate to the use of the combined Army:
1) Each Force functions independently with units ordered only by characters from the same Force and magic spells/items effecting only friendly units from the same Force as the magic user. The only exception to this is that units from one Force may support units from another force during combats (for clarity: units from two forces may not brigade).
2) The Army has a combined break point (add all the units in the three forces and divide by two, rounding up as normal). In other words, an individual Force will never break from the battle, it’s all or nothing.
3) Killing the general of a single Force will not result in that Force withdrawing. It is necessary to kill the two generals from the same Army to force the Army to withdraw (at this point the entire Army will withdraw from the battle).
THE BATTLEFIELD
The game is played lengthways on a 12 x 4 table. Terrain should be set up in a mutually agreeable manner.
SET UP
Defender deployment
The defending army deploys first. The army is set up in three deployment zones:
D1: Vanguard
D2: Main
D3: Rearguard
Units of the same force may be brigaded should be in "marching" order with no more then 2 units abreast. No more than 2/3rds of the units (not points) in any one force may deploy in a single deployment zone. '
Outriders: Both the vanguard and the rear may employ "outriders". These should be single units (anything other than Machine and Monster) which move parallel to the main army-column and in ANY GIVEN TURN may make on full move "forward", unless they spot an enemy in LOS and within 20cm or see other outriders in LOS fall back on the main army. IN either case they will make an initiative move DIRECTLY towards the central axis of the table (where they expect the main army.
Baggage train: The defending army deploys ten baggage train wagons. Five with the Main and five with the Rearguard. During the command phase Wagons may move 20cm directly towards the Defender’s exit table edge (they do not need to be given orders to do this). Alternatively they can be given individual orders (a miximum of two per turn). Wagons are treated as chariots for the purposes of terrain, they cannot be brigaded, and cannot be driven back by missile fire.
Attacker deployment
Attackers/ambushers divide their army in brigades and may start the game with 2 brigades AND their general on the table edge OR deployed in woods/built up terrain within 20 cm of a table edge. For the purpose of deployment the table should be divided into 4' sections. Section 0 being the edge where the ambushed army will try and leave the table. An attacker can opt to use any 2 adjacent zones for his original deployment and to bring on his reserves. Reserves need to be ordered onto the table, which can be done by any character already deployed (taking in applicable penalties) or by attaching a not-already deployed character with the brigade, in which case they character is placed on the desired entry point and the brigade can be brought on with one successful order.
Starting the game:

GAME LENGTH


VICTORY CONDITIONS
Victory Points are awarded normally for units reduced to a single stand or destroyed, as described on page 63 of the Warmaster rulebook. The army with the highest Victory Points total at the end of the game is the winner.
Bonus Victory Points
Escape: The defenders gain additional Victory Points for each unit of two or more stands that exits the table (Units of one stand or flying units do not count).
• Vanguard units moved of edge #0 count as HALF their value towards their armies VP.
• Main units moved of edge #0 count as FULL value towards their armies VPs
• Rearguard units moved of edge #0 count as double their value.
Baggage Train: Wagons are captured by inflicting one hit on the wagon (which has no armour and which doesn't fight back). Units engaged with enemy troops cannot attack wagons. Once a wagon is captured, remove the model from the table. At the end of the game roll D6 for each wagon plundered:
1 = 0
2-3 = 100
4-5 = 200
6 = 300
Generals: generals killed count for double victory points but their deaths do not force an army to withdraw unless all three are killed (at which point the whole army withdraws. Generals may not voluntarily leave the table until all units in their army have left the table.