I'm also trying something similar.
As said before, most Slackbuilds (official or from slackbuilds.org) have the $ARCH template.
Here's what i'm doing with some official slackbuilds, this is part of my modified glibc.SlackBuild:
# This should be i486 for all 32-bit x86 arch:
if [ "$ARCH" = "i386" ]; then
OPTIMIZ="-O3 -march=i386 -mcpu=i686"
elif [ "$ARCH" = "i486" ]; then
OPTIMIZ="-O3 -march=pentium4 -pipe -fomit-frame-pointer"
Gentoo, Slackware, <any>distro can be optimized.
Portage does it all for you with make.conf and USE flags. In Slackware you are
the package manager
You can have the "USE" flags on the slackbuilds themselves:
Anyway whatever you do don't change the CHOST setting from i486 to anything else or things will get strange
I totally agree.
Have you seen arch-linux ABS
Take a look at their /etc/makepkg.conf
The only thing i didn't like about Gentoo on the lappy is how hot it gets sometimes
Slackware Linux can run on 486 systems all the way up to the latest x86 machines (but uses -mcpu=i686 optimization for best performance on i686-class machines like the P3, P4, and Duron/Athlon).
EDIT: Oh yeah, as alphageek
having a turbocharged custom build of 'ls' won't exactly do much for you