I believe the "against the ToS" only works when you cannot guarantee the deal. If you say you're selling just the house, then the details are vague. You cannot guarantee (100%) the trade of your home to another person. If you put up something like "Pay me ten million for me to relinquish my land" it would be something you could guarantee.

However, what about selling a free company? If you sold a Free Company, with housing, that IS a deal you could guarantee.