What version of mpl are you using?

The latest, I compiled it from the source as FC5 has a very old version - can't update myself the distribution -

In recent versions, the collections should accept 2D numpy arrays as
well as any sequence of tuples (and several other possibilities).

For 2D plots, numpy arrays is accepted - but not for colors, it tells me there is a problem with tuples, I do not remember exactly, but I can check the error tomorrow -.
For 3D plots, the offsets must be special, I suppose, as the array must be iterated on with a zip, I don't know why there is this need, but I didn't write it :) This difference in format is akward :| And the fact that the example file cannot be executed is still stranger.

Autoscaling does not work well with arbitrary collections because there
is a chicken-and-egg problem: a collection member may be drawn in pixels
or other physical units, in which case its size in data units cannot be
determined until it is drawn with a given xlim and ylim (and sometimes dpi).

That is not my worst problem, I imposed the limits and it works now like a charm :)