I think "that other game company" once published a siege supplement for Warhamster, but it never really caught on. I like the idea of sieges, though. If you come up with some rules that are not too unwieldy, I would love to hear!
I fondly remember a game of Blackbloods against Firstborn taking place on a series of narrow ledges (on several levels of elevation) and rope bridges. The rest of the tabletop represented a deep gorge. We decided to forgo the restriction on missile warbands and have an archery duel. The footing was dangerous, so any run, leap, break away, charge or countercharge forced a Leadership test on the model (on their own Ld, not their leader´s), modified down by their armour minus 20 (1st edition) and up by Strength value. Failure meant the model plunged to their death on the rocks below. Models had to take a similar check if they received a hit, whether they made their armour save or not.
There were a few safe spots where models could take a stand without having to check, but they were few and far between. To top it all off we used Desert climate effects (the battle taking place between Tabukhar´s pathfinders and a Firstborn expeditionary force in the Lands of the Flame), and promptly rolled for desert twisters. They never got around to hitting anyone, but they got in the way of shooting several times and kept the archers on their toes.
We first thought the game was mostly about getting the archers into position, but quickly found that the few close combat warbands that we had taken made most of the difference by taking up key positions on the bridges and forcing the enemy archers to move around. In the end, we lost more models to falling than to any other cause. It was an extremely fun and occasionally nerve-wracking game. Marius finally kicked my Troll off the bridge with his sole remaining longbowman in close combat (the indignity!), allowing his macemen to cross the ravine and go hand-to hand with my remaining Goblin archers.
Goblins proved surprisingly hardy in this game since their low armour gave them a positive modifier on their Ld tests, and their low cost meant that I considered them expendable and took more risks with them. We both were severely disappointed with the performance of our individuals – we had expected them to be able to hold a bridge or ledge on their own, since enemy warbands had to come on one by one on the ledges, but the falling rule made most of them take the plunge before they could do anything worthwhile.
We never got around to try a similar scenario in the far north with the Sons of Kronos – I would have been interested to see if their low armour, climbing and ice warrior ability would have made up for the slingers´ poor range and damage. Also, the Dragon´s Breath or a snowstorm would possibly have given the scenario an interesting new twist.
I also imagine a similar battle could take place in the higher platforms of a Gourd Tree... or (with additional indoor rules) among a set of Elven spires. Flyers could also make a difference.
