&lt;p&gt;Riffing on how outlaw Butch Cassidy&#039;s life might have gone had he survived in South America, this modest oater should tickle Western fans. (I assume there are a few of us left.) &lt;em&gt;Blackthorn&lt;/em&gt; finds Cassidy (Sam Shepard) still in Bolivia, breeding horses, bedding his Indian housekeeper (Maga...