Redmine has a nice batch edit feature, but nothing equivalent for "batch create" (please correct me if I'm wrong!)
FogBugz lets you quickly create multiple tickets with the same properties (type, status, assignment, etc.) via a ajax-ified text box at the bottom of any filtered view of tickets. Tickets created this way match the values of the filter (and the filter grouping value - there's a text-box at the bottom of each group).
Toodledo has simpler option: it's "Add multiple tasks" feature is a textarea where each line is turned into an item.
Is there a redmine plugin out there that adds functionality like either of the above?