Sub32
From ArchWiki
Summary
sub32 is a set of scripts which help you to create and manage a i686 chroot. You can get it from AUR(http://aur.archlinux.org:/packages.php?ID=18643).
Setup
After you installed the sub32 package, you need to set up your chroot. This can be done by sub32-init.
sub32-init [mirror]
Mirror can be any mirror, by default ftp.archlinux.org is used. Reminder that you need to escape it, e.g.
ftp://ftp5.gwdg.de/pub/linux/archlinux/$repo/os/i686
turns into
ftp://ftp5.gwdg.de/pub/linux/archlinux/\$repo/os/i686
After sub32-init completed successfully, you need to start the sub32 "daemon"(well, it isn't a real daemon) by issuing:
/etc/rc.d/sub32 start
You can start it automatically by adding "sub32" to your daemons list in /etc/rc.conf. After everything is done, you may want to configure your chroot like your normal system. You may also want to mount your home to /chroot32(e.g. mount -o bind /home /chroot32/home).
Usage
Sub32 uses "profiles", scripts that are located in ~/.sub32. By default, only one profile is available called "shell". Execute it using
sub32 shell
Profiles are just shell scripts, so you can write your own and place them into ~/.sub32.