> Currently, SL 3.x and 4.x has the directory structure
> 
> 4.4/i386/errata
> 4.4/i386/contrib
> 4.4/i386/SL/RPMS
> 
> Where everything is pushed up into the arch directory.  CentOS has 
> things at
> 
> 4.4/contrib/i386
> 4.4/updates/i386
> 4.4/os/i386/CentOS/RPMS
> 

I think generally pushing the architecture type differences deeper (i.e. 
the CentOS layout) is easier to follow.  In fact, it would be, from that
perspective, nicer to do
   4.4/SL/RPMS/i386
but that's just me :-)

Marc