[roadsternut]

for the quality on manufacture and the materials involved I think it was pretty good value ( $300 ) I couldn't have got anything similar custom made locally for that sort of money !

Full custom 4-point roll bar in high grade stainless steel, made in UK, £310:
http://www.mx5nutz.com/forum/index.php?showtopic=11964&hl=

So I dare say a simple bar could be made quite easily, and relatively cheaply.

One thing I have noticed with these straight harness bars; they foul and wear the backs of seats. Probably not a problem in Japan.