Orchardup was acquihired because of an open source tool they hacked and they are discontinuing their hosting service.
Tutum has no SLA at all and explicitly recommends only using their service for toy products. Basically, they're not a real hosting provider right now, just a very expensive toy.
Stackdock has been "currently upgrading our platform and sign-up has been temporarily disabled" for months now. I'm wondering what's going on, but I wouldn't be surprised if blocking new signups for such a long time means they're about to pull the plug, for whatever weird reason. So long without new customers (while I'm sure some are leaving) can't be healthy. I really want to give them money but I can't.
Finally, the people who made Docker itself once ran a PaaS service, dotCloud. It has been sold off and does not seem to be getting much new investment - definitely not any support for directly hosting Docker containers.
In short, there are currently 0 real Docker container hosting providers (and by 'real' I mean that they will exist past October and have at least some uptime guarantees).
I really want you to be right, but currently the evidence looks very bleak IMO.
We made this same bet last January and we're currently spending way too much effort DIY'ing it all on a VPS.