Of all the outfits Arwen had in the movies, we have only one represented by Sideshow -- the Ford of Bruinen one, in bust form. The statue is based on an unused concept from a deleted scene.
So if they make an Arwen, I dearly hope it's one of the beautiful dresses she wears throughout the films. Anything from the kimono-inspired one from Rivendell, to the Greek tunic-inspired one from Aragorn's dream in TTT, to her mourning dress from TTT's flash-forward sequence, to her riding blue brocate or her red-black dying gown from ROTK, to her lime-colored Coronation outfit.
Really, why create the same thing twice when you're so spoiled for choice, and all your remaining choices are less macho than the one already made?
As for the Elves in general -- they had the most amazing costumes in the Trilogy, and anything from Arwen to Elrond to Haldir to High-elven Infantryman to Galadhrim Archer or perhaps even Gil-galad would certainly amaze.
BTW, you're right, Dave. The Istari did incarnate in human form, so we should count them as such for the design intents and purposes...