Well, finally found a Conquest 24 for my son and even though it looks small, once the seat was raised to the proper height it fits him perfectly. Leg extension is correct, reach is good and as he grows I can get a longer stem.
The problem is tires. I have not been able to find someone, locally or online, who carries road tires for the bike, let alone a cross tire. Any suggestions? What are people using on their 24" cross bikes?