What?: This is mainly meant for map makers. Essentially what it would do is just add mob spawners to the creative menu.
Why?: I do know that there are mods for this but like right now we're in 1.7.2 and all the mods are still 1.6.4 I don't want to be limited in making a vanilla map because I mod isn't updated. This would be so easy to do just like NEI does but part of the creative menu. I should also either have a gui to select the mob or just add all the different spawners in the menu. You should also be able to spawn special mobs like spider jockeys and powered creepers. This would also be great for vanilla servers that don't use plugins and/or mods.
Also in case you didn't know, for now you can use: