Is there any way to automatically generate a provisioning script based on what was installed on the guest machine? For example, I do "vagrant ssh" and then install my whole development environment and it creates a script to do it every time based on what changed?
Right now it has frontends for bcfg2, cfengine, chef, puppet and shell scripts. It's not perfect, but it does a pretty good job of giving you a base set of provisioning rules you can then refine by hand.
Not within Vagrant itself. This is really the realm of configuration management tools. As far as I know, no tools do this reverse engineering because it is a fundamentally very difficult problem, but many of the config mgmt tools make it very easy to translate shell commands to rudimentary scripts for their systems.
Vagrant doesn't, but blueprint[0] seems to be a decent tool for generating puppet manifests. I haven't used it personally, but an Ops guy at work has had some success with it.
