I have implemented a comprehensive sorting solution for AMX Mod X. It takes into account most major uses, and then provides custom sorting wrappers.
On a side note, it's rare that I'm fully pleased with code I write. But the solution I ended with came out very efficient and clever for the restrictions I had. These will be the first natives to accept and modify 2D arrays, as it turns out it's not an easy task.
You can see this in revision
2947. See "sorting.inc" for more information, and "sorttest.sma" for examples.