I’ve got a beta-quality release of Soundswitch available now.

You can also peruse the source code.

The big changes for 3.0 are as follows:

• Configure Source1 and Source2 via tray icon.
• Select current active sound device from tray icon.
• Single left click of tray icon switches between Source1 and Source2
• Rewrites of core parts to reduce bugs and increase speed.

Please let me know about bugs.