Today I visited the VKernel stand where I met Bryan Semple. He had some great news. Next week VKernel will release a new free tool called the VKernel vScope Explorer which will be great for every vSphere admin. It will give you the ability to show any problems in your environment for up to 8000 VMs. Although this free version is ment to be an overview and will not show you everything in deep technical details, it does give you very good info on the problems a VM is having. VKernel vScopre Explorer is built on the same engine of the full product and will give you similar results, it is almost a light version of the new VMware vCOMS only from VKernel instead of VMware.
Check their website for the official release.