PMD Technologies published a YouTube demo of its USB-powered 3D ToF camera:
Update: There is another USB-powered ToF camera from Mesa Imaging/CSEM. The camera size is just 4x4x3 cm^3. To achieve low power consumption it uses a higher modulation frequency of 80MHz. The camera prototype provides resolution of 7mm (std dev) at 1m and 3mm (std dev) at shorter distances.