Seeking iPhone/iPad JavaScript/jQuery libs, techniques & tutorials Client wants iPad &amp; iPhone support for a webapp that has at least one form where DOM elements are dragged around on a (Raphael) Canvas (JavaScript rendered graphic). 

Currently, the touch-unfriendly interface to drag items around uses mouse-hover and other mouse states to handle the drag-items interface. I know I'll need a completely different approach for touch screen devices, and am wondering if any fellow Drupal developers have posted their breadcrumbs as they faced this.

Drupal 6 or Drupal 7 does not matter, since this is at the JavaScript layer unless the possible solution requires jQuery only available in Drupal 7.
The only thing that I know of that's close to what you want is on Eric London's Drupal blog where he talks about themes and redirects for mobile versions of Drupal websites.  I'd be interested in knowing more about this too, sorry that I couldn't be of more help.