What I would like is to have short bits of USB A male-to-female extensions, which move. I suppose though, that each segment would actually have to be a two port hub, with an appropriate motor controller occupying one port. The male connector would have little horns on the back, and the female matching
The simplest and likely the cheapest option would be to run three muscle wires along the cable, but this would have very limited motion, and require constant power. It would be the the most compact solution, however, possibly not much larger than a regular USB cable.
A bulkier, more expensive, and more capable version would drive steppers, which in turn would drive worm gears in a toothed track. Three of these, each with ball joints on either end, would not only form and hold an angle, but also be able to extend and contract.
More expensive versions would include some form of feedback; current draw or temp sensors, or linear encoders, or whatever. Longer chains, which use a larger controller for more segments, but only a single hub, could also be made.