A good package-solution for a property company to offer would be a phased in bungalow to maisonette solution IMHO.
You build the single story guest-wing with WC for immediate move in and rent savings, then main building which could be double story or single story depending on budget..built pole pole once the client has moved in. Because if you tell them 5m or 7m or higher amount cash needed to build the whole thing most will give up without even starting but if it comes to down to say 1.5 to 2m for phase one where rent can be saved, very many will be interested. Ekeza-Gakuyo, Diamond Property Merchants and PRC type of companies please do not steal my idea and misuse it to swindle! Legit companies only are allowed to pinch this.