Well, as with many things in the World of Warcraft, there's building duplicates - inns, town halls, and such - and I found one place in Old Town in StormWind, next to S1:7 or whatever it is - where the warrior trainers are - that looks exactly like the inside of the house on GM Island but it contains NPCs and there is no surrounding balcony.
So for those of you who want to see what the inside of the house on GM Island looks like without violating Blizzard rules should just go visit the friendly StormWind warrior trainer.