Never heard of the numlock and capslock keys being inverted, ever. That's a weird one.
One question, just out of curiosity: Does the numlock key on the MacBook have a light like the Pro models? I remember that iBooks (and I think even 12" PBs) didn't, which proved horribly confusing to new users who accidentally bumped F6 and had no idea that numlock even existed.
I'm just having the same problem. I'm writing from a fresh formated macbook: New installed and the parameter
ram is zapped. All softwareupdates are done and the keyboard is inverted. The numlocklight and the capslocklight must be on, otherwise the keyboard works only in capital letters (capslock off) or as numblock (numlock off).
It is the second macbook, that must be returned! The first has had a defective superdrive.
Same thing on my MBP but only with the Num-Lock key and it doesn't always happen. Basically i start up the computer and the Num-Lock key LED in on, however i can type letters as normal. If i turn it off i go into Num-lock mode!
But as i said it only happens 1 in every 5 times i start the computer so i think it may be a software bug. And it doesn't bother me that much to demand a replacement. However the caps-lock key must be very confusing.
Just fix the darn whine Apple!!!!! I can forgive the heat and this num-lock thing but the whine seems to hit a nerve in my brain.
EDIT: Try to boot from the OSX discs and use Disk Utility to repair disks and permissions. I did that last week and i think it hasn't happened since. Not sure that will help but it's worth a try.