The workgroup code in smackx was never fully working or functional. But we have a commercial product, Jive Live Assistant that you may want to check out – http://www.jivesoftware.com/products/liveassistant. It implements JEP 142 on the server side and via a web client.
The smackx code was originally for Jive Live Assistant. However, we had to abandon the effort because we needed to make several extensions to the library to make it easier to use to use with JLA that go beyond JEP 142.
Nope, only our commercial product Jive Live Assistant implements the JEP.
Are there non-commercial jabber server that
implement jep-0142?
Not that I know of. However, building out a solution on top of the commercial Jive Live Assistant product could be an option for you. Feel free to contact me directly if you have any questions about this.