Design Patent Pending -Rights for an applicant

Unfortunately, you do not have many rights when your patent application is pending - patent rights only attach when the patent issues. However, you can certainly advertise/promote your product with a "patent pending" notification on it which effectively gives the world notice that a patent application is pending and that if/when the patent issues, they may infringe your patent. This also plays a role against those who willingly keep using the potentially infringing design once the patent issues because they were in fact already on notice that a patent could issue and yet they continued to use their product which could very well likely infringe your design when/if the patent issues.

With all due respect to Limor, pending design applications are not published.

You do not have full patent protection rights while your application is pending. However, if the application is published, you can send a letter to the Copier informing them of your application (together with a copy of it) requesting that they stop copying your design. While the Copier is not required to respond or cooperate, there is a chance that they will decide to do so.

I am not qualified to practice in the US, so this is just referential note. Please undedrstand that this is not legal advice to which any legal responsibility attaches.

Please see the following URL for example. Like the situation in Japan, you MAY be able to collect loyalty equivalent for "infringer" of your pending patent if you publish your application and notify the "infringer."
This may have adverse effect, however, to trigger the "infringer" to attack your pending application by possibly submitting prior arts to USPTO.

http://www.finnegan.com/ja/resources/articles/articlesdetail.aspx?news=46e0770f-1dd9-4866-a081-c41ecf32bd27