I'm maintaining a few of my own Vagrant boxes, because I want some truly minimal bases (that means no Puppet or Chef).
Built with VeeWee (https://github.com/jedi4ever/veewee).
Hosted here: http://lyte.id.au/vagrant/
First install RVM: https://rvm.io/
Then install all deps:
bundle install
List available definitions:
veewee vbox list
Build a box:
veewee vbox build $name [--force --nogui]
Exporting a built box:
veewee vbox export $name [--force]
Before importing to Vagrant itself, start up a fresh shell (so that you're not using RVM to access it) and run:
vagrant box add $name $boxfile