I own a Young Sun 54 designed by W I Crealock, hull # 1 launched in 1988 in Kaohsiung, and I know hull # 2 was also built by Young Sun boat yard in Ping Tong, Kaohsiung.
Don't know it. (which doesn't mean much since I'm alerted to boats new and old every day that I've never heard of.) It certainly like to include it here. But I would need a little more information.
I just happened to stumble on to this site, in case you hadn't seen it already:http://www.youngsunowners.org
I don't see any mention of the Young Sun 54 though.