Haute Hippie's cowl sweater vest is super cute, but retails for $225 at Shopbop.
This cowl neck vest from Calvin Klein does have some differences, making it a little more inspired by, but it is still a fantastic alternative for less. It retails for $79.50 and you can click on the photo below if you're interested in purchasing.
*Update - 11/9/10* - This Ann Taylor cowl neck sleeveless sweater is very reminiscent of the Haute Hippie version and retails for $49.99 (marked down from $78). Click on the photo below if you're interested in purchasing.