There was a brief trend in the very early 90s for 26x1" road bikes (nobody said 650C at that time). I remember seeing a few manufacturers pushing it at Interbike in 1990 and 1991, IIRC. The idea was that the wheels were stronger, lighter, and more aero. It's the same rationale that Moulton used decades earlier for small wheel size, but 26" was big enough to satisfy the UCI rules. Not sure if they still do.

At any rate, if this is what you're looking for, that's the time period to search. It was a pretty minor trend and died out quickly. Road bikes weren't exactly popular then anyway. They were marketed oftentimes as 'tri' bikes.