Here's the schematic.
Test Code: (UPDATED) This is a complete ISE 10.3 SP3 project targeting the Avnet Spartan 3A EVK which drives the DAC at a rate of 41.7kHz for evaluation purposes. It provides a sawtooth on the left channel and a sine on the right channel. The A and B capsense pads raise and lower the pitch and the C pad serves as a gate.
Price is $25 (US) each and $5 shipping for any quantity up to 5. Payment via Paypal is preferred. Please contact me prior to paying to ensure that I've got sufficient stock to cover your order.
Update 05-16-09: Thanks to all who have supported this project. I've sold 15 of these to customers in the US and Europe over the last few months. I currently have 5 units in stock and parts on hand for 10 more as demand requires.