Controlling handset envy is always a challenge in this business -- without fail, manufacturers inevitably introduce your phone's successor just as soon as you work up the courage to plunk down that rather sizable wad of cash. Fortunately, there's a hacker out there for virtually every model from every manufacturer, cooking up ways to keep the phone fresh well beyond its maker's intended shelf life. Such is the case here: yes, Sony Ericsson would like us to toss our K800s in the trash and pick up the re-upped K810, but seeing how our K800s still have that new phone smell on 'em, that seems just a bit silly. Users have discovered that the K800 hardware embraces the K810's firmware with open arms, bringing with it the latter's cooler themes and improved media player, and all you have to do is pay a few bucks to get it flashed. Not a free lunch, but about as close as it gets. Cool, eh? Heck, it's so simple, it barely qualifies as a "hack."
Update: Hold up! The results are in, and it sounds like the upgrade will cause the keypad lights to stop functioning properly -- a dealbreaker in our books. [Thanks, photonphox]