What hacks exactly do you need done to the coin code?
One attribute that seems kind of needed for a coin that is to be given out to gamers in a game instead of only to miners is a big stash of coins to give out.
Tenebrix already has seven million pre-mined coins, coins created in the first block, that causes so much bad press that they are now thinking of destroying those coins.
Maybe giving those coins away to players of a game would be more useful than destroying them?
Since basically all you need of a coin is that you have some to give away, that might be one good approach.
Another good approach is to use a coin that can be mined effectively by CPUs. That way the players can aquire the coin easily themselves directly, and thus actual played characters in the game, instead of the game adminitrators aka the game mechanics, can be the source of coins in the game for new players who enter the game later after even just with CPUs mining it the difficulty has skyrocketed just from the sheer number of players. Both GRouPcoin and BBQcoin took that approachj, both were CPU-mine-able for many many many months, BBQcoin is now jumped on by GPU miners, too difficult for CPU miners, and GRouPcoin looks to be headed that way too, especially as it can be merged-mined.
I have gone down this road before, I created for my players many blockchain based currencies.
The problem with blockchains is, they are insanely expensive to secure, because hashing with enough hashing power to be secure takes more and more and more hashing power as the amount of hashing gear held by people who are not defending your chain increases. The more hashing power people not defending your chain have, the more hashing power your chain needs in order not to be so low difficulty as to be ridiculously weak, way too easy for almost any bunch of lolzers to attack just for lols.
Maybe you can step through each and every already existing coin and explain how it is unuseable as a game currency, so we can get a better idea of what kind of hack job would be needed to hack up a coin that would be useable as a game currency?
The solution the many blockchain based currencies I made for my players used was to stop using blockchains, because blockchains are too insanely vulnerable to attack OR too insanely expensive to make even just a little less vulnerable but still be ridiculously vulnerable.
How do you plan to secure a chain? How many thousands of dollars a day budget do you have to buy hashing power to secure it?
It is hoped that one day when ASICs are cheap consumer goods shipped the day you order them, we will be able to set up Massively Merged Mining farms so all the chains that had to retreat to the security of Open Transactions will be able to "come out" again as blockchains, with massive hashing power securing them all via merged mining. But that will take some time yet, and of course by then potential attackers will also have massive ASIC farms...
NOTE: peruse the tables and plots at
http://galaxies.mygamesonline.org/digitalisassets.html to see that not being run as a blockchain does not hinder the value of a gamecurrency. It might in fact help it a huge amount because it is secure instead of being vulnerable to 51% attack by any and all lolzers that bought a few Avalons...
-MarkM-