I like that they're addressing this issue and think this is a good way to do it. My only concern is a semantic one: currently "d/" is the prefix for domains, "a/" for alias information (basically a global address book), etc... It doesn't make sense to create another prefix for domains (actually, many more prefixes for domains, since I imagine this won't just apply to com). I think instead they should consider something like "d/com/*" or something long those lines. It keeps DNS information all under the same prefix, and still conveys that the information is for the "legacy" com tld.