Demo is available now:

https://github.com/aakselrod/libtxchain-java

It depends on BitcoinJ 0.10-SNAPSHOT from about a month ago (hopefully not too much in terms of API has changed since then).  It requires bitcoind running locally in regtest mode, with the snapshot from here:

https://github.com/aakselrod/bitcoin/tree/stdpreimage

The only change I've committed is permitting three new templates as standard transaction types (only one of them is used in this demo, though).

This demo is a proof of concept only - it has lots of bugs that need fixing, it doesn't support any kind of communication between nodes other than within the same process, it does no error checking or input validation whatsoever, etc.  It just sets up two payment channels (between an intermediary and two endpoints), and sends some payments between the endpoints by way of the intermediary.

I'm releasing this code into the public domain.  I've timestamped the file, info at the following URL:

https://www.proofofexistence.com/detail/44020f041501aea0d01ed3e0a7dd822732e5c9945dfedc9271d19890b4a3592d

(Although now that I look at it, it looks like they haven't actually sent any transactions to the blockchain in a while... hrm...)