We've recently launched our service that helps deploy capacity across AWS EC2 spot to provide high availability and up to 90% discount on compute. Magic happens by us predicting spot prices and distributing capacity across dozens of uncorrelated Spot auctions to limit exposure to possible price spikes.
As serial entrepreneurs we know first hand how important it is to iterate quickly and reducing the compute cost is one of the ways to approach it. If your company's AWS bill is significant (>$10k/month) and you have an interesting use case that we can discuss - we'd be happy to offer a free trial access to our service for up to 6 months.
Our current use cases from private beta include web-tiers, Hadoop, Spark, Mesos tiers, and HPC workloads (Bioinformatics, rendering).
Feel free to post your questions here or reach out to us directly (and please mention that you're from HN).
Best,
Dmitry http://www.clusterk.com (http://venturebeat.com/2015/02/19/clusterk/)