Johan I have had the same thought in your OP for quite a while. For the reasons already covered, long-distance transmission will probably stay AC, but about 80% of what we use in the home is now converting from AC to DC. Go look under your desk, assuming you are oldschool and have a PC. If you are like me, you have about 6 wall-wort DC converters (ethernet switches, pc speakers, printer, external drives, router, laptop charger, LCD monitors, cable modem...). Then my media cabinet is similar (switches, routers, nas storage, tivo, etc). Heck, a lot of things which have AC plugs are just doing the conversion for you, like PC's, large printers, tv's etc.
A DC in-house, or even small-area standard wouldn't be so hard. Laptops should be getting one eventually to standardize charging,
IEC announces new standard for future universal laptop chargers | The Verge
I think the standard would be 24V, and inexpensive regulators in the devices would knock it down to 12, 6, 5, whatever. It would be one plug, different from any nation's current AC standard (no chance of making a mistake) and it would probably have an actual active communication protocol where the new device enumerates for 100mA and asks for a power budget (this is what USB does). If the 24DC plug has capacity the power is supplied. That way you could save power because you would only have one AC to DC conversion (instead of dozens) and the plugs would be small, neat and cheap. Money is saved because you don't keep re-buying wall worts and a lot of e-waste is eliminated. (raise your hand if you have box of orphaned power converters).
Part of the reason I think this hasn't caught on is that the power savings is minimal. The AC to DC converters are actually pretty efficient which undercuts the need a bit.
I have had thoughts of just doing an ad-hoc version for my desk setup. Build a custom desk with a single 12V AC to DC supply. Virtually all your little gadgets take 12V. Then you could get a fairly modest solar panel at 12V, and a 1kWh of li Ion batteries and go digitally off-grid... It pains me that I have 85kWh of capacity mainly loafing in the garage!