I've thought about it. Technically, it could be done, but it'll take some work and it'll cost some $$$ even if you do it yourself.
If you succeed in doing it--or have someone else do the work--please let us know how it went.
From recent experience (my posts relating to seat work can be found on this site), it may just be worth buying the seat you want (Russell Daylong, Corbin, Triumph, etc.).
Lastly, I'm still trying to alter an adjustable rider/passenger rest that I bought for my last bike to fit my R3T. I just may be able to do it, and if so, MAN, that will be cool!