Do any iOS Email Clients allow the folders to expand/collapse like Outlook?
The best folder management app for email I have used is eMailGanizer Pro.


  Folders
  Expand/Collapse style folder navigation
  Find folders by searching
  Add, move, rename, &amp; delete folders
  Off-line operation for later synchronization
  Universal Inbox, Unread, &amp; other 'Smart' folders
  Show all folders/labels for email