[Matplotlib-users] A collection of axvspan ?

All,
I need to plot stripes of different widths at different locations along the x 
axis, but spanning the whole range of y data. Using axvspan in a loop works 
quite fine. However, I was wondering whether it wouldn't be more efficient to 
build a PatchCollection. 
BrokenBarHCollection could be a candidate, but I have trouble figuring how to 
force the bars to span the whole range of y: is it possible to force the 
ordinates to axes coordinates ?
Thanks a lot in advance for any idea/comment
P.