[quantum_mechani]

I would use msew's rules, with the exception of capitals (i.e., you can stack as many mages there as you want without retreat orders). This would allow everyone a safe research base, while keeping the mages out of battle most of the time. While this would make players hard to kill, this is not neccesarily a bad thing. Also, you could always 'starve' the capital mages out from lack of gold.