I can't believe they haven't released this on Region 1 DVD yet! There doesn't appear to be any evidence of it ever having an official release, I would think Criterion would have bought it by now.
Even the region 0 DVDs you can find are in PAL format only, still won't work in the US AFAIK.
I rented it on VHS back in the day shortly after One made it more popular than any hippies could have ever dreamed of, great movie.
In all seriousness, you should contact Criterion and request them to look into purchasing the rights to release this. If they've got Night & Fog, they should certainly get JGHG as well.
EDIT: I just Googled to see who has the rights, and believe it or not Metallica bought the entire movie so they could use the clips in their video. They own the rights to the whole movie! They've been holding on to it since 1988, and they don't release it on DVD? awful.