More and more devices are powered or recharged through USB connectors. (Fer example, I now use a single powered USB hub to recharge a camera, PalmPilot, and GPS unit -- eliminating two power bricks.)
Hard drives that are powered just through their USB connector have been available for a year, and now LG has released external DVD burners that are also just powered by the USB cable.
The trick is getting the power and current requirements down to the 5v provided by the USB spec. I could see inkjet printers being powered by USB, but never laser printers.
Another alternative to reducing the number of power bricks is through batteries. Wireless mice now last a year on a pair of AAs, and perhaps power consumption of other devices can be reduced as well.
Yet another power source is being overlooked: office lighting. I've owned a Citizen watch since 2001 that has a solar panel discretely mounted on the watch face. It just needs one full day of sunlight to keep it running for eight months -- or some office light every day. Computer peripherals with large flat surfaces would benefit from solar/office-lights recharging:
- laptop computers
- external hard drives
- inkjet printers
Especially 3-in-1 inkjet printers-scanners, which have lots of empty space inside and so easily have room for the battery.
One of the banes of digital cameras is how they chew through batteries -- a far cry from the film-based SLRs of the 1970s and 80s that needed just a tiny sliver of a battery that lasted a year or two.
With all the work being done on power reduction, maybe we can return to that earlier age of nearly-powerbrick-free living.