Exactly one month ago, HP announced a new product called ProLiant Virtual Console (PVC) able to manage a Citrix XenServer edition that comes without XenCenter.
The product is a part of an initiative called ProLiant iVirtualization, is now including VMware and soon Microsoft (look at the bottom of the announcement).
At the moment the project involves VMware only in the sense that ESXi can be pre-installed in new ProLiant servers, but the lightweight hypervisor comes without VirtualCenter, so it’s possible that HP may want to offer a PVC for VMware ESXi (and Microsoft Hyper-V) in the coming months.