\_ Has anyone gotten mouse wheels to work on XF86 4+? 

Have you tried the docs for XF86 3 and ported them?

http://www.inria.fr/koala/colas/mouse-wheel-scroll/

Simple though, mostly it looks like this (for me in XF86 3.x):

Section "Pointer"
    Protocol    "IMPS/2"
    Device      "/dev/mouse"
    ZAxisMapping 4 5
EndSection

David