I got rid of the media a number of years ago but I had hard copies (disks) of megs upon megs of CB packet intercepts.
Everyone was using 27.540 at the time. Wasn't just KB-KB or PBBS stuff, either - there were full-blown F6FBB systems running on the frequency.
And therein was the rub: Many of said operators of the larger systems were also hams. And either through carelessness or deliberate intention, they didn't configure the forwarding rules properly and flooded the amateur BBS network with a considerable amount of non-ham traffic. Message traffic, 7-zip files and the like from "USA1NY" or "USA6CA", etc. showed up daily - if not at every hourly forwarding run. At the time I was running one of the largest MSYS BBSes in the state in terms of radio complement - 3 VHF, 3 HF (including a 1200 baud port on 28.195) and a modem port for remote management. My upstream forwarders and I got sick of all the non-ham traffic hitting our BBSes so we dropped a universal Kill rule into the forwarding configs.
This had mixed reactions from our user base. But if it's my license on the line and there's even the slightest question of impropriety, the stuff gets squelched.
Wasn't too long after that (1995, IIRC) that the FCC came down on the domestic CB packet operation like a ton of bricks. It pretty much dried up overnight.
It's sad that packet radio died a seemingly undeserved death. Still isn't permitted on our Class D CB allocation but KB-KB (no BBS) operation is permitted on the old MURS frequencies. Grab a RadShack 19-1210 and connect to a decent antenna, hook to a 1200 baud controller and have at it.