We create a base image, make sure there's only one admin account (the requirement for the approved default profile copy method), get everything set the way we want it, and then clone that VM. We run sysprep on the clone with the required answer file to copy the admin settings to the default user, join it to the domain, and then snap it. That becomes our "prepped master" that gets used to build a non-persistent pool using Quickprep.
Been doing this for three years. Works great.
Geoff