A sample can save me a thousand words:
<?xml version="2.0" ?>
<Products>
<row>0012345|Flat Monitor |21ABCDE| 21|987.65</row>
<row>0012346|Internet Keyboard|99ABCDF| 32|986.64</row>
<row>0012347|Laser Printer |44ABCDG| 5|985.63</row>
<row>0012348|Wireless Mouse |11ABCDH|108|984.62</row>
<!-- repeat 10000 times -->
</Products>
<?xml version="2.0"?>
<schema id="Products" namespace="...">
<element name="Products" type="xsd:table">
<complexType>
<element name="row" type="xsd:tuple" separator="|">
<complexType>
<sequence>
<element name="ProductId" type="string"/>
<element name="Description" type="string"/>
<element name="Model" type="string"/>
<element name="Quantity" type="integer"/>
<element name="UnitPrice" type="decimal"/>
</sequence>
</complexType>
</element>
</complexType>
</element>
</schema>
Remember, we are NOT replacing hierarchical structures, we are just extending the power of XML, when needed.