Sort of on the subject, i've seen a brochure for a specialty product marketed to law enforcement. It's meant for use with the seizure of live, powered on desktop PCs and similar that have a high likelihood of full disk encryption.
Essentially it's a medium sized double conversion ups, with a really high quality sine wave inverter, and some electronics that can match phase with a live 120vac 60Hz circuit. And a tool kit which consists of the insulated electrical hand tools needed to do a midspan removal of the cable jacket and splice into the wires in an ordinary PC power cable. The person using it is of course supposed to be trained in advance, and competent at the process of attaching the UPS to the live circuit.
Essentially it's a medium sized double conversion ups, with a really high quality sine wave inverter, and some electronics that can match phase with a live 120vac 60Hz circuit. And a tool kit which consists of the insulated electrical hand tools needed to do a midspan removal of the cable jacket and splice into the wires in an ordinary PC power cable. The person using it is of course supposed to be trained in advance, and competent at the process of attaching the UPS to the live circuit.