A virtual private server (VPS) is a virtual server operating as a service by an Internet hosting company.  A VPS runs its own copy of an operating system, and customers may have admin access to that operating system enabling them to install almost any software that runs on that operating system.

Pure SSD VPS uses only SSD drives and no conventional drives.

SSD-Cache VPS is setup for you automatically if you are using RAID.

All definitions I have found for hybrid VPS solutions point to superior resources and specifications compared to VPS solutions.

SSD drives fall into the definition of VPS solutions and are the fastest hard drives available.

While Network Attached Storage is a different subject, increased storage capabilities does go along with the
definition of hybrid VPS solutions.  In Network Attached Storage different nodes can be accesses on a network for better and more reliable network storage capabilities.

Most of the definitions of Hybrid servers I found did state that hybrid servers run on multiple individual physical servers.

The following is a diagram that shows how VPNs work