BungeePortals is a Bukkit plugin that communicates with BungeeCord; allowing you to create 'portals' of any material, shape and size in conjunction with WorldEdit. These portals will use BungeeCord to send you between your Minecraft servers.
Bukkit: http://www.bukkit.org/ BungeeCord: http://www.spigotmc.org/threads/bungeecord.392/ WorldEdit: http://dev.bukkit.org/server-mods/worldedit/ BungeePortals: http://www.spigotmc.org/resources/bungeeportals.19/