I love the idea of themed battles and the other ideas floating around on this thread..
I also like that you are prepared to use your own troops and gear for the community to have some fun and earn some EXP.
In the spirit of doing something for the community, Heskey and I would like to offer the use of our fief for a battle (or several).
I am the owner of Burglen, I don't know if you are familiar with the map but it has a village on top of a small hill with 3 points of entrance (center, left and right) and the attackers spawn on a hill with a small valley between.
Image looking at the front of the village
http://c-rpg.net/img/locations/Burglen.jpg where you can see the three point of entrance
Image from the sky
http://c-rpg.net/img/locations/Burglen_sat.jpg attackers spawn on the top left.
Due to the valley and the 3 points of entrance which bottle neck the enemy it makes shield walls very effective which would work with the 300 idea.
Terms and conditions would be on the lines of - we will put Burglen to just population with no gold or equipment.. you can then ever take over burglen for the purposes of the battle or just send Burglen the men (gold for troop upkeep) and gear and attack it yourself (or who ever you want to). Once the battle (or battles if you want several) are done, you return Burglen (if we are not currently in ownership) back in the state we left it (0 army, 300 pop, no gold or equipment). (and of course things like don't use/change any of the PP etc)
But a more formal contract can be arranged when/if you wish to use Burglen for the purposes of community strat battles