Both the receptacles pictured are available from Leviton stock, and are still produced.
Yes, the receptacles are available. But, the delta breakers in NEC2005 408.36(E) and NEC2008 408.36(C) are no longer manufactured.
I see nothing that prohibits you from using a 3-pole breaker in a single phase panel, as long as it is not being used for supplying 3-phase equipment. Notice, the NEC issue is with the number of phases
. I do not know about manufacturer prohibitions.