Something we are always looking for at work. Have a look at TRACO or V-Infinity. They do some very small units that conform to EU regulations for "touch current" etc.
It's easy to botch something together using capacitor dividers, but if it burns your house down......
RS Comps do some very small ST devices on a PCB (I can get the details if required). They seem to work OK but are not certified for general use, not EU approved despite working very well in my test circuits.