I like your descriptions of Grayceon and SubRosa - the aspects of both of those bands which are interesting to you, are among the many reasons I like them so much as well.
Jackie Gratz may be no Anneke van Giersbergen, but she's definitely coming into her own as a vocalist, and her voice lends a haunting quality to the music that's pretty much unmatched in metal. Plus, she has some pretty damn good screams on this album - the best examples of which are probably between 2:45 and 3:15 in "A Road Less Traveled".
Similarly, Rebecca Vernon probably isn't going to win any awards on national TV (thank Satan) for her vocal work, but those growls that start at around 4:45 in "Beneath the Crown" are some of the most awesome sounds I've ever heard come out of any metal artist's mouth - male or female - period. Holy fuck - are you kidding me?
Plus, the instrumentation on both albums is just so well done. There are tons of non-stereotypical metal instruments being used very creatively - and not in a contrived way, but in a way that actually adds something to the music. The violins in SubRosa just add this incredibly syrupy layer of sadness that just drips all over everything, and as you point out, the low-end in Grayceon is actually Jackie's cello. She and Zack are a rhythm section that can truly tear shit up together with the best of the standard "bass-n-drum" duos out there.
Anyway, just had to agree with you wholeheartedly on those two. You can definitely expect to see them towards the top of my list for 2011 as well.