My original Bethwaite harness was just sort of an "old style" (ie nut cruncher) harness except it had the Bethwaite bar (mine is one of the original aluminum bars) so I think any one of those would work. There are several people advertising harnesses on E-bay all the time- if you measured the bar and photo'ed (or sent them the actual bar--) I'm sure they could make you a custom harness.

Kirt