No drug company wants to become dependent on one or two products. To diversify its asset portfolio, Endo Pharmaceuticals (ENDP) went shopping this year. In cutting three deals, Endo convinced many investors and analysts that it could survive the slowing growth and generic competition that inevitably threaten all branded drugs. With a strong balance sheet and relatively low borrowing costs, Endo went on a deal-a-month shopping spree. In July, it