Unfortunately I believe this project has stalled. From time to time old GM equipment shows up in Ebay auctions. I missed a chance at an AVT made cable that appeared to be for datalogging from the ecm service connector. Would have been neat to have. I don't know if any of Bob Rauscher's Lockers schematics are available but that's the best way to get your data if you have the ability to use one.
http://www.diy-efi.org/gmecm/archive.../msg08905.html