Just got this dropped on a HM Zaishen quest. It's Req 9 Gold Domination, Maxed all over with a Basic 20% Half Cast (White).
Cheers in Advance
PC on Ensorcelling Staff
Lancer Crimson
LicensedLuny
Hmm, if you mean what I think (the white half cast part confuses me a little bit,) it's a gold, req 9 domination Ensorcelling Staff with 11-22 damage, +10 energy, 20% HSR all spells, and an inscription slot.
I haven't heard of HM zchest
but I'd guess that staff is worth maybe 10-20k max? It could be hard to get that much for the skin, I'm not sure. But I do run into a fair number of folks looking for mesmer gear in Kamadan - lots of them turn out to be looking for "pretty things" for Gwen. 
I haven't bothered to press anyone to find out how much they'll spend on her though.
If someone else comes along with a more confident answer, trust them over me.
I haven't heard of HM zchest
but I'd guess that staff is worth maybe 10-20k max? It could be hard to get that much for the skin, I'm not sure. But I do run into a fair number of folks looking for mesmer gear in Kamadan - lots of them turn out to be looking for "pretty things" for Gwen. If someone else comes along with a more confident answer, trust them over me.