Multiple Textures

I thought it be a good idea to develop a plugin(possibly once bukkit is released) that lets multiple texture packs on the server enabling us to have different themes at one time, e.g

When a town is created the mayor can choose a style and every block in that towns area used that texture pack, is will give every town a unique look and feel, the wilderness texture will be left to the users discretion.

I don't think this would be possible, as the Texture packs are linked Directly to the Client and not the Server. Would be an awesome thing to Have though :)