As much as I like designing things, at some point, I need something that works.
In that vein, I have abandoned my API design, and started work on spinning up a 5-machine Riak cluster.
The goal there is to get a cluster together, and see how much traffic it can take. Then, I start defining bucket types, and run the load test again. Of particular interest will be how quickly I can get a document to show up in read requests once I write it.
An external indexer will be required. So, I'm also going to try to get Mesos/Marathon/Spark running. It will be interesting to see how the Mesos ecosystem (which prefers Hadoop) interacts with Riak.
On the client side, I haven't progressed far since I got a Beagle Bone wired up to one of the radios. I should really get going on that.