usability - Selecting many elements from a long list

I have a scenario where my 'create user' dialog has a very long list of options, of which the user needs to select many. The project manager has suggested a 'dual list' approach: a long (scrolled) list of checkboxes for the user to choose from, followed by a list of all currently selected options. The second list would 'auto update' as the user proceeded to click them in the first list.

As suggested by the PM, it would look something like this:

(Somewhat functional "demo" of the above mockup here. The actual mock ups of the application itself are just about equally plain and ugly.)

The problem is that while the screenshot in this example only has fifteen or so options, of which only a few are selected, the real world application could have hundreds of options, and the user might have to select fifty or more. The user will always have to click fifty times, say, but what would be the best way to do this from a user experience perspective?

The project manager also suggested a 'select all' option, and keeping the lists in alphabetical order and 'synced' (checkbox select/deselect automatically updates the selected list.) The major concern for the PM from the user's perspective is that once they've selected all the options, they need some way of 'checking' to make sure they've gotten them all. The PM is of the opinion that scrolling through a hundreds-of-options-long list of check boxes will be tedious for a user to do, and that it will be easy to miss options that way.

Key points:

• A list of (possibly) hundreds of options


• User will probably be selecting many, but not all, options


• User will need to check their selections on this screen before committing their changes

This is going to be a fatiguing tasks no matter how it's implemented. I'm just looking for a way as to not frustrate the user with a clunky or ugly interface, and/or to streamline the process as much as possible.

This is very closely related to this question: Alternatives to a dual list for selecting a bunch of items from a long list? and Best way to select a subset of items in a long list?. Those questions focus on the general case, whereas I'm considering the 'whole lotta clicking' case.