New Knudarr castle has:
5% tax (eventually 9-12%)
+2 red cav robes
+2 saracen turban helmet with neckguard
+2 rus cav boots
+1 long spears
+1 crossbows
+1 war longbows
+1 heavy bastard swords
+1 long bardiches
+1 bardiches
+1 brown lion heater shields,
+1 simple swords
normal quality siege and medium ladders
Roughly 30% discount on all of these, (little higher on body armor).
Basically set it up so that you can equip every 500 troops for 100,000 silver with solid mid-tier gear.