[Answered ]-A CMS as a front end to build an applications GUI

You should stick to the language your team knows best. If it’s C++, you’ll be suprised to know that there are C++ Web frameworks available, such as Wt. A full blown CMS like Plone is overkill for such a simple use case (basically a web frontend to the database).

You should have a look at Django-CMS. It’s incredibly easy to hook application logic to any page. I use it as the base for all of my web apps.

Django was originally extracted out of a CMS, making it particularly useful for building CMS and CMS-like applications.

You should check out many open source applications that implement CMS and CMS-like features.