Custom weight paint brush callback

Hi folks,

I’ve been googling but can’t find any info-- is there a way to create a callback so that I could create a weight paint brush in Python instead of having to hack and recompile the source? Any brush, really; I wouldn’t mind knowing how to add a callback to a sculpt brush as well, but I need the vertex weight blur behavior changed for the project I’m on.

Thanks in advance.
~ k