While it is possible to buy a ready-made standing desk, many of the best standing desk designs are custom-made. Lifehacker reader Chris put together a straightforward standing desk from assorted IKEA components.
Combining the Expedit $288 cube bookcase and desk attachment combo with a pair of $39.99 Lack shelves used as legs and some basic hardware, Chris created an effective desk and storage combination for under $400. Hit the link for more details of how and why he put it together.
Standing Desk [Kythin's Rants]