You can do it on Dell Home or Dell Small Biz (USA).

You just have to start with the base configuration for any system you select, and even though the base configuration might include a monitor, you can select "no monitor' on the monitor page, and it will deduct the portion of the price that they allocated towards the monitor.

If you start with one of their special deals or advertised specials, you may not be able to select "no monitor". They have about a gazillion ways to configure the same system, but only the base method lets you choose exactly what you want in terms of hardware and software.

My comments only apply to USA Dell sites.

-David