Firstly, congratz for the awesome mod, I've been playing it and lurking on the forums for a while.
I have no experiance in modding TW, but just got a huge lightbulb flashing above my head, and it would be great if it could be implemented in this mod. IIRC in vanilla TW the last level of government building had the "Upgrades bodyguard units" property, that supposedly turned generals/warlords into armoured generals/warlord (altho I think I never actualy saw exactly how it worked, since I never got far on any vanilla game, due to discovering mods). So, the thing is, it may be possible to make a building in DA (and not buildable anywhere else) that upgrades RK's standard BGs into Knights of DA, so FMs could also get that unit, and not just recrutable generals (also I've read somewhere that the AI never recruits RGs, so that way it can have access to them). Probably even adding this to Dunland's highest level of stables (available only in Isenmarch ofcourse) that upgrades their infantry bodyguard to their mounted one (it's was kinda odd in a battle I had once, where the faction leader had to walk across the battlefield, while the lowly general leading the reinforcing army marched around on horseback).