I needed a quick and easy way to do operations on many items selected in a list in a similar manner to how the Mail app on iOS works, so I put together this simple plugin (see below for screens and a video). It is designed to work with the newer Sencha Touch 2.1 list scrolling mechanism. I'm just cleaning up the code, then it'll be on GitHub and the Market for those interested. It is still a little rough around the edges, but is usable and very easy to add to an existing list because it is implemented simply as a plugin.
Code is here: https://github.com/wnielson/sencha-ListActions
Example of how to add list action functionality to an existing list:
text: 'Delete (0)',
text: 'Move (0)',
text: 'Mark (0)',