Yes, there are a few case studies on this page: http://wavemaker.com/customers/
You can also see a gallery of customer screenshots here: http://community.wavemaker.com/Showcase/
There are also some more WaveMaker Developer Community member application screenshots here: http://dev.wavemaker.com/wiki/bin/view/Application+Showcase/
WaveMaker is a truly open WYSIWYG rapid application development tool that runs in a browser. Built on open source projects like Dojo, Hibernate, Spring, Acegi and others, WaveMaker has no black box - that means you can take the generated WAR file and either open it up in a tool like Eclipse or deploy it to any standard J2EE container safely. We don't lock you in and there's no proprietary languages you need to learn. Our goal is to make WaveMaker as easy as possible so that non-expert web developers can quickly build and deploy web or cloud applications. For ISVs, WaveMaker can not only be used as a base for their software, but they can also ship WaveMaker along with their software as a customization tool for their clients. Fun side note: WaveMaker studio was actually built using WaveMaker technology.
Hope that helps answer your questions!