We'd like things centered (text-align property).

We need some spacing between things.

The font size, bold, etc. should be changed.

One way to do this:

<xsl:template match="s:slides/s:authors">
<fo:block break-after="page" text-align="center" font-weight="bold">
   <fo:block font-size="175%" space-before="60pt" space-after="30pt">
      <xsl:value-of select="preceding-sibling::s:title"/>
   </fo:block>
   <xsl:apply-templates/>
</fo:block>
</xsl:template>

<xsl:template match="md:author/md:name">
<fo:block font-size="140%">
<xsl:attribute name="space-before">
<xsl:choose>
<xsl:when test="preceding-sibling::md:author">
15pt
</xsl:when>
<xsl:otherwise>30pt</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<xsl:apply-templates/>
</fo:block>
</xsl:template>

<xsl:template match="md:author/md:email">
<fo:block space-before="8pt"><xsl:apply-templates/></fo:block>
</xsl:template>