Hey,
I just bought my new (used) Nokia E61 from someone here on the forum (RNmac, great seller by the way). It had the Spanish keypad layout and was on v2.xx software version when I received it. I, too, had read a few comments about the battery life issue. I used the phone for a couple weeks while waiting on my new UK/US only keypad and T6 driver. During that time, on firmware v2.xx, I never had any problem like what you're describing. Last night, I swapped out my keypad for the UK only version, used NSS to hack my phone's product code to UK/Netherlands so that it would work with my new keypad, and then proceeded to upgrade my firmware to the newest v3.xx firmware. All went well. I still have no battery problems with the new firmware.
I will say that I've run into battery issues with several Nokia S60 phones. Typtically, they work great until the battery gets down to, say 50%, at which point the battery life starts rapidly "tumbling" (name my friends and I have given it...). We call it the "Nokia Tumble". Its pretty typical. There are also times when, after using a S60 phone constantly for a good long while, (and NOT seeing any dip in battery level), turning the phone off and then back on and the battery life now only showing only ONE bar or so. THIS SITUATION seems to be a battery VOLTAGE issue that the phone misreads. Usually, when this happens, I just continue to use the phone as if the battery was full and MOST OF THE TIME the battery life will come back up quite a bit (yes, by itself).
YMMV