Thanks for the input. I know the vast majority of batteries are rebranded Johnson Controls or Exide, but there seems to be a bit of variability in the specs of the batteries each different distributor sells (at least in the range of batteries I'm looking for).
For example, after checking some online battery selectors (ie.
http://www.autobatteries.com/selector/index.asp) Sears (DieHard) was the only distributor I could find so far that had a 1000 CCA battery available. Unfortunately I haven't even been able to confirm that on Sears' web site, as it doesn't seem to list the CCA (or RC) for any of their batteries. I will have to stop by the local Sears and check; that is my best choice at this point.
Autozone's is 850 CCA (Sears also has an 850 CCA and as you pointed out is almost certainly the same battery). No RC specs for that either though.
We don't have a Walmart here; even if we did they'd never get any of my money anyway. Worry not ;-).