I am writing a bachelor thesis on EDI and I would like to mention ebXML over there too, but it seems there's very small amount of information over the internet, is it still used these days?
Also part of the question I have to address is how technologies like (RPC, WebServices, ebXML and EDI) developed the data interchange.
You may be using the wrong search terms. Look for ebMS (ebXML messaging services), AS2 and AS4.