This issue also affects .sh and .ac TLDs I believe since they are the same registry. If I find out anything new I'll post on Twitter in the @dnsimple account and here.
To explain why that's useful, we have three domains, draw.io (mutter), diagramly.com and diagram.ly that all map to the same thing. The actual site runs on a Google App Engine appspot domain. On GAE, you have to buy a Google Apps for Business account to map a domain to an GAE appspot domain.
We have three Apps accounts because of this. We're not happy to do the 301 on a physical server, that loses the scalability advantage of GAE. This has always needed to be done at the DNS level ( I know it's not truely a DNS feature, but I'm assuming the scaling of the redirects at someone who does it as a service is better than mine ). This is the first time I've seen this service. That's all...