How do I go about repairing the spring tension / retractor spring on a '69 seat belt? is there anyone out there who repairs, rebuilds or sells these? I have found nothing repro other than NPD and they're asking $100.--a little steep.

RPM, I can only suggest picking up an issue of Hemmings, it will have plenty of guys out there that you can call and get a $$ idea from.

These people restore seat belts: http://www.ssnake-oyl.com/ They're not cheap by any means, you may want to shop around for some clean used pieces.