I think Waverly nailed it in the original incarnation of this thread. These sorts of descriptions of women are a staple of old blues songs. On my iTunes I have a Lead Belly number called “Big Fat Woman” and a Freddie King song called “Big Legged Woman,” and Robert Petway and Honeyboy Edwards doing takes on “Long Tall Woman Blues.” There are probably some others I can’t find right now. Bessie Smith was a whole lot of woman and I’m sure she sang about that some. That’s who they considered desirable. Or at least enough of them felt that way to repeat the description.
That’s “Born Under a Bad Sign,” an Albert King song that Cream covered. It’s not a particularly old song - King and Booker T. Jones wrote it in the late '60s, shortly before Cream did their own version - but it had been blues theme forever. Zep was referring to that. For once I don’t think it’s fair to accuse them of ripping anybody off.
I like Big Legs and I cannot lie
And all you other brothers can’t deny
When a girl walks in with a tiny waist and long legs in your face - you get sprung!
Musicians typically like their lyrical women thick, I guess
