Ordered some samples from EXAR, so exited.

Testing Arduino -> Web socket -> Ethernet shield -> node red - it works, not quite sure on speed.

https://github.com/ejeklint/ArduinoWebsocketServer

Ethernet shield I tested is wiznet w5100, (http://www.ebay.co.uk/itm/151915704260) have not tested SD Card

https://www.arduino.cc/en/Main/ArduinoEthernetShield v2 mentions W5500