There is an interesting discussion about these i-dns.net names here:
http://www.circleid.com/posts/chinas...n_translation/
These IDN.IDNs are also resolving through enabled isps (4 major ISPs in China according to i-dns.net) in addition to use of plugins. I think a couple of posters in the discussion were able to look up DNS servers (for customers in China) using punycode for these fully multilingual names.
But this is separate from Verisign IDN.com and if there were another .IDN (Verisign) counterpart created, it would likely need to be something different than this .IDN extension ending I would imagine to avoid conflict.