The kaftan certainly is a hot look right now and this Anthropolgie version is just gorgeous. It is made from silk and features embroidery and sequins sewn onto the fabric. A really easy design to replicate, McCalls 6552 is very similar in style. I haven't sewn this pattern myself (in fact it is one of the patterns that I DON'T have in my collection) but you can check out the rave reviews on PatternReview.com by searching for the pattern number in the sewing reviews. It is said to be an easy sew with a few warnings about the low neckline (wear a cami underneath).
Caftan cover up
Amy Butler - Soul Blossoms Rayon - Peacock Feathers Rayon in Sea Grass
M6552 | Misses' Dress | Fashion Star Patterns | McCall's Patterns