There is a new kit coming out that is designed as a modern replacement for the famous WW2 "Paraset" spy transceiver. It uses a crystal controlled 5W TX and a regen RX. This is an American design. I have no idea how it would hold up in Europe. I have used regen receivers, but the biggest issue was knowing the frequency you were listening on precisely. I guess it would be OK for nets but I would not want to call CQ unless I was sure the frequency was really clear. QRP signals can often be weak.