@jocke4u I run 2 RF gateways and it's not a problem. When you 'migrate' a node to a new gateway make sure to run the mysensors clear eeprom sketch first to get rid of the old routing table or you might have issues.
Finally I've solved. I'm still using UIPEthernet sincee my problem was the use of DHT library (last rev) with UIPEhernet lib.
I was having a restart of teh ETH port each time I was reading Temp/hum. I've changed into SimpleDHT lib and now it's working fine. I'm using a mix of W5100 and ENC28J60.
