So I just watched an amazing (albeit long) presentation about SSL. He brings up some great points against DNSSEC that I had not thought about.
http://www.youtube.com/watch?v=Z7Wl2FW2TcAConvergence is just about SSL certificates and trust, and not about the DNS layer.  I think a plugin that works with convergence or a standalone plugin that works on some of the same ideas could really help build a usable Distributed DNS.
One of the most important parts of DIANNA (and Namecoin or even any other distributed DNS) is the ability to trust self signed SSL certificates. It cuts out the huge and 
unnecessary job of Certificate Authorities while not reducing security.  
The beauty of convergence is that you just click a button in Firefox and it works, and IMHO we need that for a DDNS to take off.