Ultra Racing has been around awhile. I came across these 6-7 years ago. The company is out of Malaysia. I was in contact with them trying to get a group buy going, but personal crap got in the way and it never came about. I think Happynole was looking into them at some point, as well. The only downside is in order to fasten them to the frame, they really should be welded in. I know some guys have fab'd up their own.
They make all sorts of other stuff for B chassis cars, as well. I'm surprised I haven't seen more of they're stuff here in the States.