As the title says, a mod to stop mobs spawning in trees. I haven't been able to find any word from notch about this.
Yeah, I do. On a smp server, where you spend time to secure an area and want to have it somewhat visually appealing, it's not fun to have to "light up" tree tops to be safe from creepers.
Yeah putting torches on top of trees is ugly, but making a plugin that would stop monsters from spawning just on top of trees seems very hard. It could cause some lag too, after all there are a lot of trees in the world of Minecraft..
Could you not write a rule that states that mobs can only spawn on certain surfaces. I.E. Not on leaves?
I don't think it would, actually. You'd have to check the block on which a monster spawned every time a monster spawned (for which there is an event), so that'd not be hard at all. Don't think it'd cause that much lag either...