Bobu:
How do you actually judge the max current you can draw from a AA battery? My understanding is the mAh rating on a battery (e.g. 2,700 mAh) is a rough indication of how long the battery would last if you drew that much current from it continuously (so the example would last 1 hour if you drew 2.7A continously or 30 mins if you drew 5.2A continuously).
Look at battery datasheets, for example the ones at http://data.energizer.com/. These show you the voltage over time at various discharge currents.