Ok, there are a few major stumbling blocks there to create a new SP game. I'm not saying it can't be done but it would involve Alot of time and effort.
One of the main stumbling blocks are the thousands of voice .wav files you will have to create for the new storyline. The file for these is quite a monster when you look at it. Depending on how many people you have doing the voices would dictate how long this would take.
Also the coding in doing a whole new storyline is very time consuming to be done right. Now anyone could slap together something and put it out but if you want a high quality product that would fit in seamlessly (well as much as you can modding..lol) with the original engine it will take some time to do this.
Having said that I am sure there are a few developement groups that are working on this, but have not announced it yet since this is a hard cookie to crack...
Hunting those above the law.
Protector and cofounder of the Hawk Trading Company found on Hals2003Evoserver.