Report: Alcan May Sell Unit  NEW YORK (Reuters) - Alcan Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AL.TO target=/stocks/quickinfo/fullquote"&gt;AL.TO&lt;/A&gt; &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AL.N target=/stocks/quickinfo/fullquote"&gt;AL.N&lt;/A&gt;, the  Canadian aluminum maker, is considering a sale of its rolled  products business in a transaction that might fetch \$4 billion  to \$5 billion, after in May announcing a plan to spin the  business off, the New York Post said on Wednesday.