Vinyl Trim = very flexible (more-so than unheated PVC).
This is exactly what I ended up doing. I got a few 12 foot lengths of 1"x2" cellular vinyl trim and a heat gun and was able to very nicely heat and bend and finish nail it in. The stuff is not too cheap but it has spared my sanity and looks way better than I could ever cut it myself, and as a bonus it will never rot!
Thanks for all the suggestions guys. I'll be sure to throw up a few pictures when I'm all done.