Security enhancements with Chrooted Apache?

Hello list, I compiled Apache 2.xx with PHP5 from the sources into a chroot environment. The only executables in this chroot-cage is bash and the apache-daemon. Only the necessary libs are in the cage. The hole chroot-tree is on an iso-image and only the partitiones needed for var and tmp mounted noexec. I want to know if there are any worries about this configuration. e.g. could anybody escape out of this cage, if he cracked apache? Thanx Kai