Apparently there are all kinds of goodies in that dump, like previously unknown betas of MS-DOS and OS/2, but there are no links to the dump itself. It's a shame that the community is so secretive about this :(
Someone got access to the full tape backups for two warez BBSes (The WaREZ HouZE and Piper's Pit) and uploaded the tape images to archive.org: https://archive.org/details/ibm-wgam-wbiz-collection. The collection spans the late 1980s to the late 1990s.
Apparently there are all kinds of goodies in that dump, like previously unknown betas of MS-DOS and OS/2, but there are no links to the dump itself. It's a shame that the community is so secretive about this :(