JPRS has published on its website "Interim Report on DNAME Technical Evaluation" which was performed by JPRS.
This report explains how DNAME resource record works with some of major recursive DNS servers if it is used to implement IDN ccTLD.
Interim Report on DNAME Technical Evaluation
http://jprs.co.jp/en/Report-20080929-DNAME.pdf
Reference:
DNAME (Non-Terminal DNS Name Redirection)
http://www.ietf.org/rfc/rfc2672.txt