Reinventing the Wheel?

Wikipedia has its own style guide. In crafting this, the volunteers are, in some limited ways, attempting to unify British and American usage, and perhaps worldwide English too. I was wondering if they were attempting to reinvent this wheel, and set off on the internet to see if anyone else had attempted this.

Once upon a time I pondered the various branches of mathematics, and could see no discernible structure, that is, an organizing overview of the entire field for the layman. I postulated a "math tree," a sort of pre-Wikipedia concept. But then I checked on other organizational schemes and realized the Dewey Decimal System had already classified math in its scheme. Whether it's a good system is not for me to say, but it's very well established. There also are other mathematical classification systems. It's not entirely solidified, though. But research tells the tale. In other words, it's useless for a layman to try to reinvent the wheel, it's better to just search intelligently. Think.

So I looked around on the net and haven't found any record so far of any successful attempts to unify British and American English. I'm sure book publishers have traditional different layouts for different audiences and readers. The United Nations has document style guides but seems to have adopted Oxford Dictionary and BBC English style by default as templates before adding their own particulars, so it does not seem to be an attempt at unification of any sort.