Why would you need a "single" receptacle for a microwave or dish washer? Fl IAEI just had this discussion and found no way to cite this as a requirement. The closest they came was the single for a fridge on a 15a circuit and even then you could plug a clock in that circuit. The 2008 has eliminated the exception for dedicated appliance receptacles that don't need GFCI in unfinished spaces so I am not sure where you need a single receptacle now.
