While I have no doubt that you of all people could do DNS right, it seems a bit like scope creep IMO. I'm very excited about sr.ht, but also worried that it might be too much to execute all at once.

That being said, DNS records in Git sounds kinda neat. You avoid all the special authentication nonsense of "DynamicDNS" or proprietary APIs by using SSH keys, and you have versioning for rolling back configurations. Also you don't need a special UI that essentially builds zone files as you'd just have your users make their own. You might need some validation of the files before you actually put them into BIND though.