I don't like it when people repost stuff in a blog but given that this is in Japanese I feel it is justified. It appears as though some kind soul has successfully put together a demo of NyARToolkit using Java Web Start. The link to check out is here:
This is great news! Now (hopefully!) I can dispense with my patchy installer and rely on JWS as my means of launching Filippo. It appears to also only work on Windows for now but we can work on that as time goes on.