I can't see a "seized" cv joint to cause the wheel to lock up. Steering would be difficult to non existant but the wheel would contiue to rotate, no different to a drive shaft without a cv joint, i.e solid rear live axle..
Thinking about it, locking up is the wrong word to use - it siezes in position and like you say you pretty much lose steering. The locking up of the roadwheel was a result of the joint up siezing whilst at a sharp angle. A similar sensation to what I would imagine driving a car with a locked front differential would feel like - rather a handful!