Well the Archos 5 has a resistive touchscreen so thus it can except any input I'm not sure about devices with a capacitive screen. Anyways I think Wacom achieves what they do through software and a special layer in the capacitive touchscreen that allows inking, palm rejection, and right clicking with a Wacom stylus. anyways I will see if this works on capacitive devices.
edit: I tried this on my brother's iPod touch and it didn't work at all.