I try to create demos for the most innovative Drupal modules I wrote. If people can try and play with it without having to download and install the module, they’re more likely to start using it. And actually seeing some functionality, can help you see potential use cases for it much faster.
- Hierarchical Select — download (2007—2011)
- CDN integration — download (2008—2012), running live on this site
- Mini Panels (part of Panels 2) — download (2007)
If any of these module does almost what you want, but not exactly, don’t hesitate to contact me to ask if your desired feature can be implemented. (But if you know how to use Drupal.org’s issue queues, then please look there first.)