Probably wouldn't sell too many, many people home brew their own ISP connectors, it's not excessively difficult. I made an ICSP adapter using only two 10 pin IDC connectors on the same ribbon cable and some male header connectors to go into a breadboard. It looks just like an old parallel IDE connector with the connector in the middle except they're closer together to get over that little gap in the breadboards center so you can bring half the pins to the other side of the breadboard, which is all the adapter needs to do.