That'd be a cool idea, especially for large servers with multiple towns. Maybe throw in a secret spawn or two in a hidden location for people to find. ;P
Actually it's a pattern in the most of MMORPG (world of warcraft, etc.), but nobody still didn't make anything like it for CB.. found the similar idea — http://forums.bukkit.org/threads/multiple-spawn-points.4623/
I've suggested this as well http://forums.bukkit.org/threads/multiworld-universal-spawn-thing.6913/ I wish I had skillz so I could write the damn thing myself.
nerdnosyd, as far as I can understand your request, you demanded a single one spawn point for your multiple worlds, didn't you?
actually, they can, via MyHome e.g. by the way, I posted the another idea close to it — http://forums.bukkit.org/threads/build-your-own-spawn-point.8328/