If you'll do a search for GPU on these forums, I think you'll find it would be a core programming implementation, and not something that could be accomplished with a plugin.
Yes, it would be nice, and I am sure the core developers are working on it as we speak. However, such a major rewrite of the code is likely to take years to accomplish, and all we as users can do is be patient and wait for an announcement!
Next to making this program reliable during rendering, I would rate GPU rendering next. As Sony generally does not consider customer feedback a priority I doubt this will come any time soon.
;(