I'd really like this also.

As my set of lists grow, I may split a list into two using renaming to facilitate this.

Then I have to copy by hand the tasks from the original list into the new one. This is tiresome!

You can. It's in the "more actions" drop down. You can also do it with multiple selections!

Along these same lines, I would like to be able to copy tasks (not just move) from one list to another -- this way I could create template list that contains 5 steps for completing a project. When the project comes up again, I could copy the steps into my Work list from the template list.

Copy tasks does make a lot of sense. That would be a welcome feature.

Another vote for a task copy or duplicate.