I\'m currently experimenting with build script, and since I have an ASP.net Web Part under source control, my build script should do that at the end:
To follow-up to @Chris, ESX is extremely scriptable. A client I've been working with recently has built a web service that launches a VMware script to create the VM they need, then start the VM with a custom boot ISO. That ISO includes all the kickstart or unattend.txt info it needs to do a totally unassisted OS build.