I haven't heard of it being released, and after a quick Google search, found that while Sha Na Na has had a couple of concert videos released, both on VHS and DVD, the variety show apparently has not.
I found one web site encouraging people to write in to the production company at
http://www.geocities.com/sistermagenta/snndvd.html.
I remember it as being an ok show when I was a kid (many years ago
) but I'm not sure how well the show has aged. Maybe they could release a "Best of" compilation disk to gauge/raise interest...