I'm not sure what my local PoCo's response would be to a request for residential 3-phase. I don't THINK there's a specific policy against it, although I don't doubt the installation charge would be higher. With 1-ph 240V 100A now standard for new services, most folks have ample power for their needs.
About the only place normally to see 3-ph in a vaguely residential application is a large guest house. The IEE doesn't like the idea of the (eek!) "general public" getting close to 415V, so they specify that all recepts. in each room should be on the same phase.
