I just registered here to let you know that I found someone who wrote an awesome python script which converts the host files from https://github.com/StevenBlack/hosts
You'll find it on github, too.https://github.com/naveednajam/Little-Snitch---Rule-Groups
It works fine though, but the only problem so far is, that when you have such an amount of rules (nearly 70000 blocks) the Little Snitch Network Monitor doesn't respond anymore (had to deactivate it) and Little Snitch needs way more memory than before (800MB). Perhaps obdev is able to fix that problem in a later update. So it's not the perfect alternative to host file based blocking yet. But I'll try and play a bit longer with it.
Don't activate all rules! I'm not even able to start the configuration to disable the rules. There seems to be a huge CPU and memory problem with Little Snitch while it has a huge amount of connections to handle