I think MailPoet gets pretty close, you can setup a template, drag and drop posts, etc. You can even have it send via Mandrill or Railgun, etc if you want.
Otherwise it doesn’t seem like it would be that hard to to setup the generated HTML. It’s really the “choosing posts” that’s the hard part since there’s a ton of ways to go about it.
You could spit out a custom template and whatever posts you want based on date but I’m guessing you want more flexibility. If I was creating this for a client, I’d probably use something like Advanced Custom Fields Pro with a settings page where you’d pick which posts—maybe with a repeater field—and then spit out the generated HTML somewhere based on those settings.