Interesting petition at:
Is there actually any existing ready-to-use standard that could be mandated stem the current bewildering variety of connectors and specifications for DC power supplies ("chargers") for digital consumer-electronics devices (phones, cameras, PDAs, printers, etc.)?
This is clearly an area that needs some work. If there really are good reasons to have different voltages and maximum currents provided by the supply (9 V, 12 V, 15 V; 2 A, 3 A, 5 A), then perhaps a little negotiation protocol a la power-over-ethernet (48 V) or USB (5 V) would be the right approach? It might add a dollar or two to the cost of the individual charger/supply, but would lead overall to enormous savings by reducing the number of chargers required in a household.
Markus