I already owned the gray-brown HEMNES desk when I decided to make it into a standing workstation. I found the new LACK TV unit and bought it in white. This cost about $15. Instead of installing the shelf at the recommended level, I raised it to just 3.5 cm from the top so that I could hang a SUMMERA keyboard tray under it. Since I already had the desk, this hack cost $25 to make a standing desk. We liked it so much my husband did the same hack to his desk at his office. He used the black LACK TV Unit. He is able to support 2 monitors on it. His was featured in the company newsletter by the employee health nurse!
BTW, I am 5’4″ and he is 6′ tall. We are both able to use this desk because our elbows (like most peoples’) are at the same height.