(Disclaimer: I haven't found any solution I really like... so the problem may be me.)

It turns out that installing and configuring services on a server touches many files and only some of them are important. Even the basic assumption that Ubuntu is the same everywhere wasn't quite right. Linode has some of its own packages installed and I think they tweaked the kernel. Running it in VMWare, you probably have the guest additions installed, etc. These things aren't important, but Blueprint doesn't know that. So I ended up with this massive number of changed files and the tooling for filtering through them to get just the important bits wasn't so hot (or at least it wasn't a year ago).