I just want to go ahead and bump this thread again since I've had a chance to again visit the environment I was in (~300km away) when I made my last post, claiming there was no difference.
Well, turns out there is a difference. A big one. It could be several factors though, and PowerManager.Display and PowerManager.Wakelocks are still the largest contributing wakelocks when "Android OS" skyrockets and keeps the phone from sleeping. It must have something to do with either devices connected to the network you are connected to, or wifi networks interfering with the network you are connected to, or something with the router you are connected to etc. because it is not normal.
As soon as I connected myself to the single-AP WiFi-network, my battery drain was up to 6 %/hr which is a LOT. In my normal environment, my battery drain is about 1-1.5 %/hr, so still some drain but much much smaller. The normal environment I usually am in is also a single-AP WiFi network.
So to conclude, both environments are single-AP WiFi networks with a lot of networks around (apartment buildings, 10+ networks in range). The only difference between the two environments is the amount of devices (TV's, computers, phones etc.) connected to the AP at once. It is therefore difficult to say what it is that is causing the drain, but I'm pretty certain it's something with the WiFi module.
I've had wifi wakelocks before, but not this time around even though it seems to incorporate wifi. Not really sure what to do, just putting it out there.
Has kitkat solved this problem?