[abrigham]

To be honest, I don't think an app like this could be made... while its true that the TP2 has a resistive touch screen, which could potentially measure the amount of pressure, it would only do so at a single point, i.e. where the stylus is pressing or the center of where your finger is pressing. I don't believe it would be able to measure the amount of pressure being applied over an area, which is what would be needed to "weigh" something... I've never really looked into the touchscreen drivers for these devices so I may be wrong, but based on my understanding of the way these screens work, it doesn't seem possible.