The largest Shorai Lithium-Iron (LiFePo4) battery has a nuclear plant-like 540 CCA. My Touring spins like a sowing machine in high gear when I go to start it. Expensive, but weighs a fraction of the lead-acid and cranks like mad. (Haven't read the thread to see if lithium was already mentioned, but possibly not since it's an earlier thread.)
Should be this (not 100% sure I recall the polarity correctly, it's either this or the A3 model):
http://shoraipower.com/lfx36l3-bs12-p130
Expensive as hell? Sure, but worth it. Exactly the same size as the stock battery, just goes from 320 CCA to 540, plus entirely different cold-weather starting characteristics (gets stronger with each try, not weaker.) Not that I've tried starting the bike in really cold weather with it.
Here's a video from a competitor, Ballistic Parts, of their LiFePo4 battery, that's another option than Shorai (but I like that the Shorai is stock size, installation is completely painless) that demonstrates how the batteries act in the cold:
These are also completely invulnerable to the usual sulfation issues that lead-acid has to deal with. They self-discharge very slowly if disconnected from the bike, no need to trickle charge if you leave it off for a winter (though the custom charger for them is definitely advisable, no battery likes being overly discharged.)
Edit: I'm on the second year on it and it has been flawless.