I don't think Extending is impossible, but there is waaay too many houses.
If you added that, and say 1/2 of the 500 + houses extended twice, thats an extra 2 levels per house, which is another 500+ levels.
I Think more customizable outsides of the houses (ability to use all the different wall/rooftypes of a kingdom) would a be wonderful addition.
And I like the being able to put stuff on tables idea, and the Kick/Key commands.
Spells are disabled for a reason, leave it be, but other than that the menu sounds good.
New furniture would be nice. (Armor racks ::drool:
