The cartridge slots can be extended outside the case with an extension cable/board (we are currently working on it).
The unit can also use a regular DC power supply (2.5mm barrel type) and has connectors for VGA/RGB (with scanlines generator), composite video, joystick, 3.5mm audio jack, microSD card and PS/2 keyboard. External USB/audio/joystick2 are available through pin headers
We would love to hear from you about this new boards. Any comments or suggestions are very welcomed!