VAGRANT_CWD can be set to set the CWD of `vagrant`.

CHANGELOG.md

@@ -7,6 +7,8 @@
     TTY (and hence can't confirm). [GH-779]
   - Fix an issue with the `:vagrantfile_name` option to `Vagrant::Environment`
     not working properly. [GH-778]
+  - `VAGRANT_CWD` environmental variable can be used to set the CWD to
+    something other than the current directory.
 
 ## 1.0.0 (March 6, 2012)
 

lib/vagrant/environment.rb

@@ -56,6 +56,7 @@ module Vagrant
       }.merge(opts || {})
 
       # Set the default working directory to look for the vagrantfile
+      opts[:cwd] ||= ENV["VAGRANT_CWD"] if ENV.has_key?("VAGRANT_CWD")
       opts[:cwd] ||= Dir.pwd
       opts[:cwd] = Pathname.new(opts[:cwd])
 

test/unit/vagrant/environment_test.rb

@@ -20,6 +20,10 @@ describe Vagrant::Environment do
       instance = described_class.new(:cwd => "foobarbaz")
       instance.cwd.should == Pathname.new("foobarbaz")
     end
+
+    it "is set to the environmental variable VAGRANT_CWD" do
+      pending "A good temporary ENV thing"
+    end
   end
 
   describe "home path" do