Preseed udev rules. Run these in a late command...especially useful when you want to bond devices.

gistfile1.txt

#!/bin/bash

# this sucks, but I want my devices enumerated the way I want them
declare -A mac_devices

mac_devices["aa:bb:cc:dd:ee:f1"]="eth0"
mac_devices["aa:bb:cc:dd:ee:f2"]="eth1"
mac_devices["aa:bb:cc:dd:ee:f3"]="eth2"
mac_devices["aa:bb:cc:dd:ee:f4"]="eth3"

UDEV_NET_RULES="/etc/udev/rules.d/70-persistent-net.rules"
echo "# This file was at least partially configured via pressed late command" > $UDEV_NET_RULES

for MAC in `ifconfig -a | grep HWaddr | awk '{print $5}'`; do
  for i in "${!mac_devices[@]}"; do
    if [ "$MAC" == "$i" ]; then
      echo "SUBSYSTEM==\"net\", ACTION==\"add\", DRIVERS==\"?*\", ATTR{address}==\"$i\", ATTR{dev_id}==\"0x0\", ATTR{type}==\"1\", KERNEL==\"eth*\", NAME=\"${mac_devices[$i]}\"" >> $UDEV_NET_RULES
    fi
  done
done