Mythruna

If you have played too muchi in minecraft likew me you will know what is world edit, in one of my posts I posted a video to take reference to the lines.
World edit is a very nice tool to edit huge structures like towers or smalls too, like your house.

a nice tutorial:
http://www.youtube.com/watch?v=lc42-LvvwbY
he have not installed the mod to see lines between selection, world edit is needed to other cool addon: world guard, you only need to select the area, write a command and this area is protected by you...

The ingame one? It would also be cool to have the Non Ingame one too Like MCedit
http://www.minecraftforum.net/viewtopic.php?f=1022&t=15522

When there are more mods and stuff... this will have to be something supported by mods.

I'm going to primarily concentrate on making the role playing game.  I add some simple things to the pure build mode when it's easy or really necessary... but an in-game editor is kind of a lot of work. :)

Besides, at some point there will be building templates and ways to place them and size them... this might be similar to a world builder.  When the NPCs and the world generator generate buildings it will be based on a library of templates... shapes, architectural styles, etc..  It might be possible for me to give the player some control over that.

And as far as external tools to edit, that's one of the reasons I created the external tools section and posted the Java notes on how to connect to a world database... because another player was asking me about it. :)

yes, I know it, is nice too :)