We use Falagard with a custom look'n'feel. All GUI windows are defined in XML-Files and almost no UI elements are created by C++ code so the UI design is highly customizable.
Rastullahs Lockenpracht (in English: Rastullah's gorgeous head of curls) is an open source RPG engine for RPG modules based on the German pen-and-paper RPG system Das Schwarze Auge (also published as The Dark Eye).
This techdemo is a showcase of the current engine's feature set, but it's not a game yet since it is still lacking some important features like combat or AI.
Our project is in German and we still have no internationalization support included but we put up an English language pack replacing the quest information texts and the subtitle texts in the dialogs with the NPCs (voice acting is German only).
Our inventory prototype

The dialog with a NSC (made from the first techdemo since we accidently removed taking screenshots while talking to an NSC)

Another screenshot from within the techdemo

Other screenshots can be found on our homepage
You can download the demo via this link.
If you don't have current MSVCRT runtimes installed, use the included MSI to install it, if it complains about how the file cannot be read, try to rename the msi to vccrt.msi, if this doesn't help, download the latest Windows-Installer Redistributable
To apply the language pack decompress the english.zip into the "Rastullahs Lockenpracht Dharai" directory and thus overwrite all dialog and quest files.
Please read the readme.txt for instructions on controls and further informations on known issues.
Our forum is located at http://forum.team-pantheon.de.