why not make list items collapsible ?
Just a thought - list items
http://jquerymobile.com/demos/1.0a2/#docs/lists/index.html already offer so many styling options, including thumbnails, sub text, chevrons at right, inset etc. Instead of having a less-stylable, always indented collapsible
http://jquerymobile.com/demos/1.0a2/#docs/content/content-collapsible.html, why not allow the general list items to optionally have a collapsible section ?
I think that would be simpler and at the same time more general than having a separate collapsible widget....
<li>...normal stuff in a jQM li
<div class="ui-li-accordion">...contents of this</div>
</li>
The chevron icon on the right hand side (already present for list items with an A tag, could be re-used for a open/close icon if the item has a ui-li-accordion div.
See also
https://github.com/jquery/jquery-mobile/issues/issue/580 which argues that explicit markup for various LI components should be used to allow additional JQM widgets to appear in the collapsible section (currently this is almost impossible because of the way the listview plugin does the markup enhancement.)