Well they likely won't actually be called Witch Elves, but not sure what their name will be right now. AoW just posted up this pic of their forthcoming regiment box on Facebook. They look pretty good and considering how stupidly expensive GW's Witch Elves are (and you only get 10 for that price), these could be a very good alternative:
EDIT: They are now up for pre-order from the AoW website. Couple of pre-order deals avaliable:
35 Euros gets you 20 Vestals of Nemesis + an exclusive Concubine of Nemesis figure.
or...
35 Euros gets you 30 Vestals of Nemesis.
All figures are plastic. compare that to £35 for 10 from GW. These aren't as nice and don't have all the extra bits to make Sisters of Slaughter with, but for making a big block of Core troops I know where my money would be spent.