application.html.erb

<%= stylesheet_link_tag stylesheets_path(:package => :desktop) %>

asset_app.rb

class AssetsApp < ActionController::Metal  
  include ActionController::Rendering

  def stylesheets
    @output = ''

    Dir.glob("#{Rails.root}/app/stylesheets/#{params[:package]}/**/*.css*") do |filename|
      sass_options = { :syntax => :scss }
      sass_options[:style] = :compressed unless Rails.env.development?

      @output += Sass::Engine.new(File.open(filename, 'r').read, sass_options).render
    end

    response.headers['Cache-Control'] = "public, max-age=#{1.year.seconds.to_i}" unless Rails.env.development?
    response.content_type = 'text/css'

    render :text => @output
  end
end

Gemfile

gem 'haml', '3.0.18'

routes.rb

Sqoot::Application.routes.draw do |map|
  match "/stylesheets/:package.css" => AssetsApp.action(:stylesheets), :as => 'stylesheets'
end