These kits are made by Obtronix. These appear to be very nice quality.
I will be replacing the plastic A3 and A4 PROM chips with 6301-1J ceramic chips that I have already had programmed. Note also that these kits include the DIP sockets! These were not included in the Obtronix kits (at least not mine).
UPDATE Apr.11.2010: Increase the reliability of the ACI by replacing the .01uF filter capacitor with a .1uF capacitor - see Mike Willegal's detailed analysis and conclusion here.