something like this in the contract model

gistfile1.rb

class Contract < ActiveRecord::Base

  has_paper_trail
  acts_as_restful_list
  
  CHANGE_FIELDS_MAP = {
    'contract_status_id' => {
      :association => 'contract_status'
      :field => 'name'
    }
  }

  belongs_to :sales_rep
  belongs_to :contract_status
  
  def get_change_value(field)
    if map = CHANGE_FIELDS_MAP[field]
      send(map[:association]).send(map[:field])
    end
  end  

end