Just had an idea. Besides trademarks, there are also patents. Like I was saying earlier, companies patent everything they can. So I was thinking, there are surely patents out there describing exactly how their satellite data feed worked -- that could possibly even clarify the VBI vs. audio subcarrier-based data feed issue.
Unfortunately, patents expire after 20 years, so all patents that applied to their 1981 and 1985+ systems are now gone and are not indexed by any of the usual patent sites (already checked all of them). Those sites don't index expired patents. And only one web site I've found indexes those -- http://www.latepatents.net -- and it doesn't seem to return anything for United Video.
Donno if you guys wanna dig deeper than I did, but yeah. Just another potential lead.