Got it.... stupid me...

<xsl:template name = "domain">
	<xsl:param name="rows" as="element(row)*"/>
	<xsl:for-each select="$rows">
		<xsl:value-of select ="./N2"/>,
	</xsl:for-each>

With XSLT 2.0 you don't need the for-each,
       <xsl:value-of select="$rows/N2" separator=","/>
suffices (well unless you want a comma after the last N2 value).

	Martin Honnen
	http://msmvps.com/blogs/martin_honnen/