Script to automatically create VirtualBox VM, booting from iso with custom kickstart and simple install. VirtualBox 4.3.0 cannot do ipxe boot on host having Core Duo cpu, so here's simple workaround - boot from iso and automatically use custom kickstart:

port=`VBoxManage list -l vms | grep -E 'VRDE property: TCP/Ports' | awk '{ print $5; }' | tr -d '"' | sort -n | tail -1`
port=$(( $port + 1 ))
mkdir ~/VirtualBox\ VMs/${name}
VBoxManage createhd --filename ~/VirtualBox\ VMs/${name}/${name}.vdi --size 16384
VBoxManage createvm --name ${name} --ostype RedHat_64 --register
VBoxManage storagectl ${name} --name satactl1 --add sata --controller IntelAHCI --bootable on
VBoxManage storageattach ${name} --storagectl satactl1 --port 0 --type hdd --medium ~/VirtualBox\ VMs/${name}/${name}.vdi
VBoxManage storagectl ${name} --name idectrl1 --add ide --controller ICH6 --bootable on
VBoxManage storageattach ${name} --storagectl idectrl1 --device 0 --port 0 --type dvddrive --medium ~/Downloads/CentOS-6.4-x86_64-bootonly.iso
VBoxManage modifyvm ${name} --memory 1024 --cpus 1 --cpuexecutioncap 50 --pae off
VBoxManage modifyvm ${name} --nic1 hostonly --nictype1 82545EM --hostonlyadapter1 vboxnet0
VBoxManage modifyvm ${name} --audio none --usb off
VBoxManage modifyvm ${name} --vrde on --vrdeport ${port} --vrdeauthtype null --vrdemulticon on
echo "${name} RDP port is ${port}"

Create iso from netinstall, copying isolinux/ dir, modifying isolinux.cfg similar to this:

label linux
menu label ^Install basic system
menu default
kernel vmlinuz
append initrd=initrd.img text ks=cdrom:/anaconda-ks.cfg

Create iso for use:

# mkisofs -o ../CentOS-6.4-x86_64-bootonly.iso -b isolinux/isolinux.bin
-c isolinux/ -no-emul-boot -boot-load-size 4 -boot-info-table
-J -R -V "CentOS 6.4 Custom ISO" .