I've been working on one for a while now. I'll hopefully get a writeup posted soon. However, I can't see it ever being available for $40 like the Tank Mouse...

I've been working on one for a while now. I'll hopefully get a writeup posted soon. However, I can't see it ever being available for $40 like the Tank Mouse... the 3 switches alone cost $12, and the Pixart sensor is $13 unless I manage to find a cheaper source.