When I encounter a split-index (A-Z) page it can be quite frustrating if I don't know the first letter of what I'm searching for.  I want to use my browser find!  For example, tonight I wanted to look at all the functions that END in "Window" in the Chart package -- no luck:
  http://hackage.haskell.org/packages/archive/Chart/0.13.1/doc/html/doc-index.html

Therefore I propose that even when generating the "A-Z" individual pages that there also be an "All" option for the single-page version.  Attached is a patch against haddock's HEAD (darcs get http://code.haskell.org/haddock/ right?) that implements this behavior.  As an example, here is FGL's documentation built with the patched haddock:

  http://people.csail.mit.edu/newton/fgl_example_doc/doc-index.html

The great thing about hackage being centralized is that if people are happy with this fix it can be widely deployed where it counts, and quickly!

Cheers,
   -Ryan

P.S. At the other end of the spectrum, when considering a central index for all of hackage (as in the below ticket) maybe it would be necessary to have more than 26 pages,  I.e. Aa-Am | An-Az or whatever.
    http://hackage.haskell.org/trac/hackage/ticket/516#comment:6