Zeppelin demonstrates some influence, I agree, but Sabbath actually started out as a jazz club band.
Even Peter Criss of Kiss played Jazz long before he hooked up with Kiss.
Ever heard any really early Judas Priest? When they used to wear frilly outfits?
You can definitely here it in the drumming on the early work of many bands that eventually became the heaviest influences of Eighties metal bands,but you have to go way back.
This is one of my all time favorite examples:
[youtube]http://www.youtube.com/watch?v=Tfn6z6HYZj8[/youtube]
_________________
I'm not likely to be around much longer. As before when I first signed up here years ago, I'm finding that after a long hiatus, and after only a few days back on here, I'm spending way too much time here again already. So I'm requesting my account be locked, banned or whatever. It's just time. Until then, well, I dunno...