Create a hyper-converged array with what you have in your datacenter
Another solution to consider in the "software-only" camp is Atlantis USX. Recent in-depth article by Chris Mellor on USX http://www.theregister.co.uk/2014/05/29/atlantis_takes_on_vipr
USX installs on the hypervisor (VMware-only for now) and works with server RAM & flash as a performance pool, while aggregating any storage on the network (flash, SAN, filers) as a capacity pool. The server admin dials in the performance, protection level, and capacity via USX for the VM at the point of provisioning. Storage characteristics defined by software - like a Nimble hybrid array, a Pure AFA, or Nutanix hyper-converged. Allows you to run up to 5x more VMs on the existing storage in your datacenter.