Reddit user u/HugoMaxwell has posted a very interesting project he is working on that is designed to radically improve the speed of plotting, with the stated goal of getting a proper GPU plotter working.
The claims made in the reddit thread are quite interesting, and I will be following this project closely. HugoMaxwell claims to have experience writing GPU mining software for the coin XPM.
As always, do not run unvetted code on critical machines. At no point should this plotting software be run on a machine with access to your private keys.