Barcodes for Python is a library that can create EAN-13, Code-128A, Code128-B, Code128-C, and Gs1 barcodes. It also includes a CLI tool that can generate barcode image files and GTK+ and Qt GUI examples with printing support. The barcodes is produces have been verified using a cheap Deltaco (KB Wedge B519153) CCD handheld barcode scanner.
Trojita is a Qt IMAP email client. It is a pure Qt4 application with no additional dependencies. It has a robust IMAP core implemented using Qt's Model-View framework. Standards compliance is a design goal. It has support for bandwidth-saving mode aimed at mobile users with expensive connections. In addition to the usual SSL/TLS connections, the server can be accessed via SSH. It has on-demand body part loading, offline IMAP support, and safe dealing with HTML mail (actually more robust than Thunderbird's).
SecureCam is a video surveillance system with a nice GUI. It supports multiple camera and video file inputs. It detects motion in input video using fast algorithms. Alarm notification is provided by email, alarm sound, and video recording. Currently, only a Windows installer is provided, but the source can be compiled on Linux.
SLD Calculator is a GUI to calculate the characteristics of chemical compounds, especially the Neutron and X-Ray scattering length densities that are often required to know in scattering experiments. Furthermore, it offers internationalization support and is capable of switching the language at runtime.