Has anything changed for you? We are having the exact same issue with one app. We submitted four apps, three were approved in less than 36 hours, the other has been stuck in "UNDER REVIEW" for over two weeks. We have also sent numerous emails through "Contact Us" to no avail.
We consider a variety of factors as we evaluate each app for Kindle Fire Tablets, including the quality of experience the app offers and compatibility with the device. While our goal is to offer a broad and compelling assortment to Kindle Fire Tablet customers, not all apps available through Amazon Apps are currently available on Kindle Fire Tablets.