Here are the statistic I have come up with for the Beastmen Chariot. I basically used the guidelines on pg 121 of the main rulebook.

Beastman Chariot
Light Chariot	M	WS	BS	S	T	W	I	A	Ld	Int	Cl	WP
Chaos Beastman (2)	4	4	3	3	4	2	3	1	7(6)	6	7	6
Boar (2)	7(5)	3	0	3	3	1	3	1	3	4	4	4
Boars are difficult to control and prone to running away. All rout test and all psychology tests are taken using the rider's characteristic as normal except with a -1 modifier.
Models Per Unit: 1-4 Chariots Points Per Model: 48 Weapons: Hand Weapons Armour: None Boars have a Natural 6+ save Options: Scythed Wheels +20 points Any Rider May have: Shield +2 points Light Armor +4 points Additional Hand Weapon +2 points Double Handed Weapon +4 points Flails +2 points Throwing Spear +2 points Halberd +4 points