What's the landscape look like for dynamic Heroku scaling?

Scaling Heroku workers is pretty easy -- you can do that with reasonable reliability in your jobs themselves. Scaling Heroku dynos, however, is a bit trickier. It seems like this area's a good target for a SaaS approach.

Unfortunately, the landscape right now looks pretty wretched. HeroScale is dead as far as I can tell (it claims to be "back in mid-February" and it's now May), and the few gems that try to do this are buggy, unmaintained, or both.

Is there a reliable solution out there?