While browsing through the library, I discovered that USGS has, in fact, produced some metric maps at 1:25,000. One example is Thendara (NY), 43075-F1-TM-025. As far as I can tell, those maps are sporadic. I do find some at the USGS website. What is the nature of this series? Is it a past project since abandoned, is it only for some areas, and does it exist in place of or in parallel to the imperial 1:24,000 series? What areas are covered by those maps?
Unfortunately the answer to many of your questions is tied into the history of the USGS mapping program and decisions made, reversed, and reimplemented along the way. I don't know the specifics for that exact scale option, nor a more current version of the resource mkennedy mentions. I stumbled across a pdf earlier from I thought 2011 where a USGS official was talking about the conversion to metric or the production of a parallel 25k series (it was related to military mapping), but I can't find it again. The best current(ish) summary I can find is this article. More information on the history of the mapping program can be found at http://nationalmap.gov/ustopo/history.html
One way to find areas covered at the 1:25k scale is to visit the USDA/NRCS Geospatial Data Gateway. On the right side under
I Want To... is a link for
Find Available Data for the US which will take you to an index, and if you scroll down you'll find a dataset that is an index for 1:25k maps. They have a map that shows covered regions. I don't know that you can download an individual list of the maps available, but you can check by state (
Order by State in that same
I Want To... menu) and it will tell you how many there are, as well as where and with a preview.
Also note that at the link provided in your question you can click on
Advanced Search and search by scale - although the results with just that criteria are more than 200, which is apparently all it displays.
Not a complete answer! I don't know how to identify what areas had 1:25,000 mapping done. You might try searching the Federal Register based on the information below.
USGS published Maps for America (3rd edition, 1987) by Morris M. Thompson. On page 109, it states
"By 1978, published 1:24,000-scale topographic maps were available for about 70 percent of the conterminous United States and Hawaii. With the general changeover to the metric system in the United States, the 7.5-minute series will eventually be produced with metric contours at a scale of 1:25,000. A few States have agreed to adopt the 1:25,000 scale before the completion of 7.5-minute mapping at 1:24,000 scale."
Based on the map in the book that shows the current state as of September 30, 1980, the map you found might have been in an area that had only 15' maps up to that point. Or, at least, was near that area.