your ATmegaxx8 and ATtiny2113 target boards are great little experiment boards. I have used them in a few projects and now I have some ideas for minor changes to the ATmegaxx8 board. For example, allow for DIP-16 packages in the prototyping areas instead of DIP-14. This would fit 74HC595 shift registers, L293D motor controller, etc.
Technically this wouldn't be a problem I believe, but I have no idea how do this for $3 a pop in small quantities. How did you manage to make those target boards so cost efficient, well really cheap actually? I understand that your design is single layer to keep the cost down. Nonetheless I have not found a pooling PCB fab house that would do this at this price in small quantities.
Do you have any suggestions? How do you make the boards for your products in general?