Here is a dead RAID post-mortem (hopefully this will help my fellow AskDifferent friends)...
I provide my experience here to help you move on from a bad hardware dependency and to confirm that eSATA is not for serious business critical applications.
Hardware RAID is like the Honey Badger - - it don't give a shit - - bad data is bad data.
First, if your RAID dies, focus on preserving the data. Clone the RAID drives ASAP. Use a separate system for recovery.
In the meantime, replace all of the hardware involved rather than trying to piecemeal troubleshooting the internal card, the eSATA cable, and the external RAID enclosure. New problems popped up for me as I went along because I drank the Kool-Aid of "it will be ok, my RAID hardware says my RAID is normal and intact".
I learned that the term "Initialize" in the Highpoint hardware RAID utilities does not mean the same as Mac hard drive initialize. The enclosure I was relying on had hardware RAID inside, but because the internal eSATA card was intermittently working a while before it completely failed, a majority of my drive data was corrupted.
Do not try to change the RAID settings with any utilities, including the Highpoint utilities, just clone the drives, recover the data, and come back to the problem system later.
My internal eSATA card had failed, but my enclosure had hardware RAID, so if you are in the same situation, do not treat it the same as a RAID pass-through card or a card-based RAID. Do not take apart the RAID logically with utilities. Do not pull even one drive out of the Sans Digital box or you will lose the RAID, period. Do not use DiskWarrior on the volume, it will break the file and folder structure beyond recovery in this situation.
Highpoint driver support for Mac is absolutely horrible for anything before Mac OS X 10.10, so let me save you the days of frustration and hours of your life from being wasted in dealing with Highpoint as I have. The Highpoint driver did not fail gracefully - - it dismounted my volume, froze my system for about twenty minutes, then when it came back, all of my launch services were trashed, and the keychain corrupted - - unreal. I could not find any RAID settings within the settings files as they were before. I never backed up the external enclosure settings or the settings for the RAID card as I should have. Other things were broken in my admin and my root accounts, so this became a complete OS recovery / reload as well.
Never throw away and driver CD or DVD for any piece of hardware you own. I replaced the dead card with an exact replacement from Highpoint online, but the CD had changed, and the Highpoint Mac installer on the DVD did not work for Lion! Yes, you heard me, the original card, same exact version, came with a CD that was different in that Highpoint had abandoned any version of Mac prior to OS X 10.8 - - all of the GUI for the web interface was there, but the HWRaidManager utility was not, and nothing worked as before.
Some more process monitoring on startup and comparison with data from the original drive content allowed me to trace the issue back to a couple of kext files. Found some replacements online (even though the Highpoint tech support could not), and modified one of their newer installers to work with Lion.
Do not expect the drivers for the Highpoint RAID cards to work consistently on Lion. Highpoint rebrands their hardware RAID utility for other vendors in the RAID market, and is so lazy they did not bother to make a different interface for Mac users.
The good news is Highpoint started reworking their drivers and Mac installer packages when they started having Mac OS X 10.8 permission issues.
Third, I started data recovery with third-party software. I monitored how pathetic the external hardware was behaving by this point in the recovery process.
As I confirmed the last bits of data from the RAID volume were recovered, I promised myself that I will never buy another Highpoint product or any product which bundles a Highpoint card with it (such as the Sans Digital product line) again.
Going with a $5K setup in a 2U rackmount solution in a mini-SAS combo from ATTO and OWC instead.