Multi-region databases

Does anyone know of an extension to the database class that supports multi-region read/write clusters? I searched around a bit and wasn't able to find one. Figured I'd ask before I write one myself.

If it had IP geolocation built in that would be ideal but I can build that on my own easily enough if it doesn't. Ideally I'd like an array of database connections set by country and a master write connection. Then throughout the code an easy way to specify if the query is a read or write, writes always go to master and reads use the closest region to the user.