SimpleXML is really nice for loading/converting XML data into native PHP data structures. I was considering crude searching of SVG for the width/height and since it really is an XML file... I found a SUPER easy method for parsing out the information I wanted:
<?php
// putting incomplete SVG data inline for readability
$RawXML = <<< XML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
xmlns:dc="http://www.example.com/dc"
xmlns:cc="http://www.example.com/cc"
xmlns:rdf="http://www.example.com/rdf"
xmlns:svg="http://www.example.com/svg"
xmlns="http://www.example.com/"
xmlns:sodipodi="http://www.example.com/sodipodi"
xmlns:inkscape="http://www.example.com/inkscape"
id="svg2"
sodipodi:version="0.32"
inkscape:version="0.46"
width="586.25"
height="743.75"
xml:space="preserve"
sodipodi:docname="some_svg_file.svg"
inkscape:output_extension="org.inkscape.output.svg.inkscape">
<!-- portions removed to keep this short -->
</svg>
XML;
$svg = new SimpleXMLElement($RawXML);
$height = $svg['height'];
$width = $svg['width'];
echo "The width x height is: ${width} x ${height} \n";
?>