Parametric minOccurs, maxOccurs?

I'd like to restrict the number of elements in a <sequence> by an attribute,
e.g.,

<!-- desired, but not currently valid, XML Schema -->

<complexType name="VectorI">
    <attribute name="Size" type="integer"/>
    <sequence minOccurs="Size" maxOccurs="Size">
        <element name="ValueVectorI" type="integer"/>
    </sequence>
 </complexType>

This seems like it would be a pretty common schema feature.  Is there a way
to do this?

/eric rehm
singingfish.com
rehm@singingfish.com