Right here is your last best bet: http://www.sakuramartialarts.com/Martial_Arts_Weapons_Manrikigusari_Chain_Kusari_p/wea-9012-a1.htmI bought a couple of these a while back just for the swivels and made a very nice pair with them. 99% identical to dolan swivels (these are a tiny bit shorter on the sides!) ..... find some round head wood screws on ebay and a couple of washers and you're in business!
usanunchaku.com is selling u-swivel's and fairly nice looking roped chucks as well.