This might be an interesting use case for the micropayments code we wrote in java for bitcoinj:
https://bitcointalk.org/index.php?topic=244656.0You could get paid for each block instantly rather than having to cash out at the end (zero trust). Also, perhaps you wouldn't need to open an account then.
As Minecraft is also written in Java, you could make a patch to the minecraft.jar file that integrates a Bitcoin wallet directly into the app. Then you could just send coins to your Minecraft instance, log into the server and have it automatically collaborate with the server mod to pay.
Using micropayment channels in both directions, it might be possible to have a new game mode - pay as you go. So you could log in and pay per minute of gameplay, or perhaps just pay a bit whenever a block is mined. So whoever mines the block gets everything and all other logged in players pay "value of block / number of players". If you want to keep the mugging element of the gameplay you can still have a cashout base.
We were talking about this very thing last night after we saw the post via Reddit. We're gonna look at the details this week. Anyone we could correspond with to answer our questions on the bitcoinj side of things?