It's been possible since Alpha 1.2.6 but was "rare" back then.
just west of my snowglobe thinger there is natural lava at the surface
I think PB's image is just intended to be a general guide, I know I've seen iron higher than 64
It's not my image!
There's two reasons though - they're not hard boundaries, but probabilities, and they've changed over time.
There's some people who have used level editors and done graphs of actual distribution. Might be interesting if anyone has done that for each release to see how things have changed.
You're spawn trick works great!
You /are/ if I say you are!
I can /spawn fine /every time/ but /home puts me in the ground /every time/. Rather fucking annoying.
What about if you find a pit dug all the way to bedrock (with water in for safety), then jump over that and do /sethome before you fall.
Where does /home put you then?
:-& I haven't got time for that!
I'm sure Jon would let you use his hole.