Ray Spencer at Crow cams did one for an American Econo Racer called 'JR' with a Cross-flow engine in 1990. There wasn't the demand for anything more than that one cam, and there was no follow-up article. I think Tim Britten did the article, also interviewing and previewing six cylinder gear by Lynx, Crow, Redline, Yella Terra, Hemi Performance, and many others.
Call or e-mail Crow Cams in Australia, and ask Ray about it. It's in the Street MACHINE series on Hot Sixes, 1990.