column_reader.rb

module ColumnReader
  def column_reader(column_name, options = {})
    name = options.delete(:as) || column_name.to_s.pluralize
    behaviour_module = column_reader_module(column_name)
    column = columns_hash[column_name.to_s]
    
    behaviour_module.module_eval %{
      def #{name}(options = {})
        connection.select_all(construct_finder_sql(options.merge(:select => '#{column_name}'))).collect do |value| 
          v = value.values.first
          #{column.type_cast_code('v')}
        end
      end
    }
    extend behaviour_module
  end
  
  private
  
  def column_reader_module(column_name)
    module_name = "Raw#{column_name.to_s.camelize}Access"
    if constants.include?(module_name)
      const_get(module_name)
    else
      const_set(module_name, Module.new)    
    end
  end
end

column_reader_demo.rb

ActiveRecord::Base.extend ColumnReader

class Animal < ActiveRecord::Base
  column_reader 'id'
  column_reader 'name'  

  named_scope :dangerous, :conditions => {:carnivorous => true} 
end

Animal.names 
#=> ['Lion', 'Tiger', 'Zebra', 'Gazelle']

Animal.names :limit => 1 
#=> ['Lion'] (Normal finder options supported)

Animal.dangerous.names 
#=> ['Lion', 'Tiger'] (Scoping respected)

Animal.ids
#=> [1, 2, 3] (Values cast correctly)