Is there any S/W that will let me check the RAID status on an ESXI Server

I would try this: http://www.veeam.com/vmware-esx-monitoring/buyit.html

To check the RAID status on VMware ESXi server, the hardware and ESXi must have in-built support via OEM CIM providers to check the "management sensors" in the server. Only then can the status of the hardware be reported to VMware ESXi.

For Dell products, a custom version of VMWare ESXi, an OEM version is either installed, or Dell OEM Management VIBs are installed and enabled on the VMware ESXi server, these are then enabled by changing a variable.

IBM Servers RAID functions can also be monitored by using the MegaRAID drivers that are loaded into the ESXi server.

What server do you have?

The servers are Super Micro. I had heard of custom ESXI versions for different H/W but when I contacted VMWARE about them they had never heard of them.

I would suggest contacting Super Micro to see if they have written VIB's for ESXi

And of course a management tool or possibly they have used another manufacturers raid controller.

To check the status of the raid  controller on any server that the OS is something you cant use to access the software, Does the server have a Remote access card.  I know on Dell  and HP servers I can get to the controller throught the RAC card .

Hope this helps.

All supermicro can tell me is to contact their resellers, they don't answer any sort of direct questions.