I think your are out of luck.
You could consider paying to increase your fare to W on flights where you could use a GPU, but if that is out of the question, then that particular benefit is naturally of less value to you. While you can't sell or barter such instruments, you could be Santa and offer to free upgrade some FT'ers (or friends/family/coworkers who do travel in such patterns, especially with RPU's) before they expire. Although even that is hard with R not opening up on more and more routes...
