Great post. I am currently doing something very similar and documenting the process :) I'd recommend chef librarian over soloist though.
The bootstrap then becomes something like
gem install chef
echo {"run_list": "recipe[pivotal_workstation]"} > node.json
chef-solo -j node.json -r http://example.com/pivotal_workstation.tar.gz
The JSON could of course be customized if you needed to set any attributes.Soloist itself is just a tool to simplify generating a runlist and specifying node attributes. In fact, it just reads out of a single YAML file and does what that file says. It even gives you what might be considered role support.
Plus we totally take pull requests!