Quick and dirty multiple file editing in one window for TextMate - Add the command to a bundle (I use source) with: keycombo ⌘S, save document, discard output. Upon saving a file with the 'scratch' extension the script will parse out all the included files and write them to disk IFF they are in the scratch file's directory or a subdirectory thereof

command.textmate

#!/usr/bin/env ruby

require '[..]/scratch_file.rb'

if (file_name = ENV['TM_FILEPATH']) && File.extname(file_name) == ".scratch"
  ScratchFile.new(file_name).write!
end

example.scratch

#file "models/post.rb"

class Post < ActiveRecord::Base
end

#file "controllers/post.rb"

class PostsController < ApplicationController
end

#directory "tests"
#file "models/post.rb"

class TestPost < Minitest::Test
end

scratch_file.rb

#!/usr/bin/env ruby
require 'fileutils'

class ScratchFile
  DIRECTORY_REGEX = /^#directory "((.+\/)*[^\/]+)\/?"\s*$/
  FILE_REGEX = /^#file "(.+)"\s*$/
  
  def initialize scratch_file_name
    @scratch_file_name = scratch_file_name
    @working_directory = File.dirname(File.absolute_path(scratch_file_name))
    @directory_prefix = ""
  end
  
  def write!
    files.each do |name, lines|
      if should_write_file name
        FileUtils.mkdir_p(File.dirname(name))
      
        lines = lines[1..-1] if lines[0] == "\n"
        lines = lines[0..-2] if lines[-1] == "\n"
      
        File.write(name, lines.join)
      else
        puts "!! Warning: File #{name} is outside the working directory (#{@working_directory}) of the scratch file. File NOT written."
      end
    end
  end
  
  def files
    {}.tap do |files|
      current_file = nil
      
      each_line do |line|
        if new_directory_prefix = new_directory_prefix_for_line(line)
          @directory_prefix = new_directory_prefix + '/'
          current_file = nil
        elsif file_name = new_file_name_for_line(line)
          files[file_name] = (current_file = [])
        elsif current_file
          current_file << line
        end        
      end
    end
  end
  
  def each_line &block
    File.foreach(@scratch_file_name) do |line|
      block.call(line)
    end
  end
    
  def new_file_name_for_line (line)
    if new_file_name = line[FILE_REGEX, 1]
      return File.expand_path("../#{@directory_prefix + new_file_name}", @scratch_file_name)
    end
  end
  
  def new_directory_prefix_for_line (line)
    line[DIRECTORY_REGEX, 1]
  end
  
  def should_write_file (file_name)
    File.dirname(file_name).start_with?(@working_directory)
  end
end

Added ability to specify a common directory, to avoid typos. I avoided refactoring the class this time but if it gets any more complex I just might.