Yeah, they're neat little beasties. I prefer the keyboard on these to the Duos. I personally have three or four of the 100s, but only one works. Two have some random problem that I've never diagnosed properly, and the third looks like someone squished it, causing the trackball to crush the screen (there's a giant, permanent pink blob now).
But yeah, good luck on getting those! They're hard to find in good shape. And let us know if there's a way to rig up a new battery.