[Blama]

No. Component XML cannot be described by a DTD, and even XML Schema would prevent many of its more powerful features from being used.

Instead, errors and warnings appear in the server console as the XML is processed.

While this is true and is also true for .ds.xml files, you could create your own schema and extended it as needed.
I did so for .ds.xml, which enables Eclipse to validate my files as well as to IntelliSense-complete my tags and attributes. See this thread.

Best regards,
Blama