The existing closed-source tools "megamgr" and "megamon" are the most piss-poor and non-scriptable pieces of crap I've ever seen.
The old MegaRAID driver at least had a human-readable /proc interface in Linux 2.4, but if you want to use Linux 2.6 (and there are dozens of reasons, mostly performance) then you're stuck with the legacy driver (older than the one Linux 2.4) or the new one without a human-readable (script-parsable) /proc interface.
So I'm stuck inferring the interface from the source
Judging from mailing lists, there isn't a sysadmin in the world that's happy with managing/monitoring these cards under Linux.
If I write an open-source utilty to do it, I'll be a god among men.
Update: okay, not so much of a pain as I thought. drivers/scsi/megaraid/mbox_defs.h seems to be the goldmine.