Using this method, pages can be selected from a selectbox in Symphony, and output into the entry you want to match against. Then a template needs to be created for each option in the selectbox, and the xsl will match against it. Caveats are that the entry needs to be manually passed to the template, as root context is broken.

gistfile1.xslt

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<!--
    Pages Section Templates
    Templates for the display of content from the Symphony 'Pages' Section

    This is a slightly hacky technique to allow the template to be chosen in the XML.

    Pages are driven by content templates, so the mode for each view should reference a content template

    xPath:  *[section/@handle = 'pages']/entry

    @author     John Porter <jporter@buginteractive.com>
-->


<!--
    Create a variable of this document's templates
-->
<xsl:variable name="content-templates" select="document('')/*/xsl:template[@name]"/>


<!--
    Page Entry as a List item
-->
<xsl:template match="*[section/@handle = 'pages']/entry">
    <xsl:apply-templates select="$content-templates[@name = current()/template/item/@handle]">
        <xsl:with-param name="entry" select="."/>
    </xsl:apply-templates>
</xsl:template>


<!--
    Content Template: Content Page
    The word 'content' must be the output of the selectbox in the section
    A template for displaying a visually rich content article
-->
<xsl:template match="xsl:template[@name = 'content']" name="content">
    <!-- The entry node must be passed in to the template -->
    <xsl:param name="entry"/>

</xsl:template>

<!--
    Another Template: Different Page
    The word 'another' must be the output of the selectbox in the section
    A template for displaying a visually rich content article
-->
<xsl:template match="xsl:template[@name = 'another']" name="another">
    <!-- The entry node must be passed in to the template -->
    <xsl:param name="entry"/>

</xsl:template>


</xsl:stylesheet>

would just match="entry[template = 'sbl-value']" be better ? I use this a lot...

I don't know what you mean. Can you show me an example?

@nitriques do you mean something like:

*[section/@handle = 'pages']/entry[template/item/@handle = 'about']