I found this while looking for a source of CCKW harnesses. It says 6x4 but the SNL doesn't really make any difference except for AFKWX models. I plan to call and get more info. These are 2009 prices.
1944 GMC TRUCK Military /model CCW 6x4
1. Dash Harness 266.00
2. Headlight Harness 147.00
3. Body and Taillights Harness 329.00
4. Generator to Voltage Regulator Harness 50.00
5. Starter Switch to Ammeter Wire 24.00
6. Ammeter to Battery Filter Wire 8.00
7. Ignition Switch to Ignition Filter Wire 6.00
8. Starter Sw. to Compressor Motor Cable [opt.] 76.00
9. Positive Battery Cable 50.00
10. Negative Battery Strap 30.00
http://www.riwire.com/
They do sell wire by the foot. If you have an original to copy it would be way cheaper to do that. They also list connectors.