Beyond designing solutions to run on CMS solutions, we have helped to build two open source content management solutions, firstly we built an open source content management system from scratch called Contour CMS for Grails. Later, another CMS solution for Grails called Weceem CMS started to gain ground, and we moved our efforts to this CMS solution.
This site is running on Weceem, so as you can see although in early days, its already self hosting and hosting this site along with quite a few others.
A quick look in the Java community will show that we have been active in the open source community. This means that we have a good source level knowledge of the products that we work with. Making time wasting much less likely. If you want to see our credentials in this area, please contact us using the link above, and I will be more than glad to provide details.