I blogged about what I thought could possibly make a better stylus recently and thought I'd sketch what I was thinking. The above picture shows how I think you could hack the Pogo Sketch stylus so it will glide a little more smoothly on the iPad screen. The capacitive foam creates a little too much friction to feel natural to me.
I drilled a small hole in the foam and inserted a plastic nib from an old pressure-sensitive screen stylus into the center. I then sawed off the back of the barrel and inserted a metal skewer into the back end to hold the nib in place.
The spring was actually part of the old stylus nib, and actually works well for adjusting the pressure when drawing--pressing hard makes the nib recede and the foam makes more contact.
The photo below shows what I ended up with.
Seems like a simple way to get past the problem of drag on the screen.