I've had some bass stands built for 3 drums which worked out well. My first experiment was with a small xylophone stand. It was not ideal because it was so tall. My next was welded from scratch by a very creative maintenance man. I sketched out the plan with 22"-20"-18" drums in mind. It was a rectangular frame with large pneumatic tires with one end swiveling like a grocery cart to help with mobility. The welded cross members were critical in placement to allow access with mallets to the heads and to have the drums support the 18" drum above. I used foam rubber between the drums and the frame to avoid unwanted vibration and bunge cords to hold in place.
Having the drums arranged vertically gives the best sound. The commercial stands that arrange the drums like timpani lose the tone quality and pitch since the sound is directed at the ground. I have not tried building a stand for 4 drums. It would be more problematic for the player to see the drum major and reaching all the drums.