For all of the 90s I flew LAX-FRA-LIN or ONT-ORD-FRA-LIN and return every 3 months. At least 25% of the time at FRA they would ask me to turn on the PC and/or do a swab test. Since the end of 2000 I have been to LIN 3 times. Most recently May. Glad I don't fly regularly anymore.
Most devices these days use a USB style charger. So only one is needed for phone, tablet, e-reader, etc. And they most likely use 110-240 volts AC so they are good worldwide. All that is needed is a plug style adapter. PC generally bricks use the same AC voltage range so only need style adapters.
Anyone who travels internationally and does not carry their power supplies and style adapters for every country they traverse in carryon should be seated in the rear lavs.