Stantum's technology is a software-based refinement to resistive touchscreens that allows for accuracy beyond the pixel density of the display, a complete lack of touchscreen "jitters" and some fairly incredible input methods. So it Nokia N900 has the hardware (Which I think it has) then a software update can load Stantum into is as well. Correct me if I am wrong
Here is how Stantum-type touch-panels are manufactured: 1. Two thin and transparent (glass or plastic) overlays are covered with conductive material 2. The material is patterned in rows on one side and columns on the other, transforming the layers into a matrix of conductive tracks. 3. The two layers are assembled superposed, the conductive sides facing each other and separated by a spacing material (transparent dots, air, etc.).