The bottom of this page has some links to contemporary wushu and taijiquan for health. I wouldn't be surprised if there is some good stuff down there hiding out.
http://dragongate.ciao.jp/kpta/But, there is a long tradition of militant resistance going back to the Sengoku period, so there is likely some great Japanese stuff, too. A lot of Ueshiba's prewar students filtered through Sasebo.
Here's some stuff that popped up on the first page of a google search for taijiquan:
http://www.kumamototaikyokuken.com/http://culture.jeugia.co.jp/lesson_detail_56-3659.htmlWho knows what might pop up if you do some more searching for other arts. Fukuoka City is right next door and is one of top ten largest cities in Japan, so don't give up without trying.
Edit: Ed, you're in Tenjin? Did you train up here and then move down to Fukuoka? I guess Ed would know if there was anything good and well known down there.