As mentioned, official support is only for parallel SCSI on Adaptec cards. Others have reported various SAS drives combinations working, but support for those would have to come from the manufacturers, not VMware.
...My biggest fear is the guest OS not being able to see and use the non-standard physical hardward such as the SCSI card.
Depending on what OS the original is, you may be able to use VMware Converter. If you can use Converter, I'd recommend using a second machine to be a temporary host for the converted virtual machine . Use Converter to create a VMware Workstation type virtual machine. Run that virtual machine on the second machine using VMware Workstation or Player. (Player is free. Workstation is available as a 30 day trial, which should be long enough for this purpose.) Once you've confirmed the virtual machine works, then you can reload the Dell 2600 with ESX. Then run Converter again, converting from the Workstation to ESX. (Technically, there's not much to convert in this virtual-to-virtual conversion, so Converter will just be doing a copy. But using Converter this way is probably easier to understand for non-Linux folks.)
...I want to use Symantec System Recovery to back this up then put ESXi 4.1 on the Physical Server. Afterwards I am going to put reinstall the Server that I placed on Symantec System Recovery Image as a Guest OS....
I assume you mean Symantec Backup Exec System Recovery. If so, then you'll still need Converter to inject the appropriate drivers into the guest OS. After you create the virtual machine and restore the image into the virtual machine, run Converter, choosing Configure instead of convert. BESR does have a "restore anywhere" option, but you need to supply the drivers, so it's something you'll probably want to practice a once or twice. Using a second machine with Converter & Workstation will allow you do practice as much as you want without destroying the original host.
You didn't mention if you were going to reuse the hard drives when you load ESX. If you were, I'd recommend using the Converter method to create the virtual machine, or at least use a new set of hard drives. That way, if you do need to roll back, you don't have to reload the the OS and backup library software from scratch. (Yes, BESR should be able to restore, but Murphy is always watching. :smileywink: ) A new set of drives may be especially important in order to test your SCSI card with the virtual machine. If the SCSI card or tape drive does not work within the virtual machine, you may have to go back to physical, which would be relatively easy if you don't erase the originals.