I think this kind of information should stick to Runescape, and not migrate to World of Warcraft. The fact that houses would be an ok idea, with use of a portal and such, but the fact that World of Warcraft would be copying off Runescape's idea is plain wrong.
I'm not stating that it's a complete failure for an idea, but something a little more original. Next people will be asking for butlers, cars, and such..