I knitted this summer halter for my daughter.
Here http://www.knitty.com/ISSUEsummer08/PATTthira.html
is the pattern. It is easily adapted to older girls, though one might not consider doing that at first look. To knit this for my daughter I only used 2.5 skeins of the Elann Esprit. Quite a bargain.
Here http://www.ravelry.com/projects/newamy/thira it is on my Ravelry page.
And a pic as well.
Thanks for looking!