• C library (libc/glibc)
• Resolver for nameservices (DNS, NIS, …)
• Authentication information (/etc/passwd, group, shadow, …)
• Additional libraries like libz, …
• If You want to run CGI scripts, additionally
• Shells (bash, tcsh, zsh)
• Perl, Python, whatever scripting language the cgi's use

the more clean approach is to install RPM itself inside the chroot() and afterwards install the whole system using the ready-made binary RPMs. This is the same like what the normal RedHat installation procedure does if You are installing on a new system

Refer to http://ftp.gnumonks.org/pub/doc/chroot-howto.html