Thanks @Ennui--after a lot of Googling, pestering people in multiple forums and asking four different designers, I came to much the same conclusion. There, sadly, appears to be no generally accepted term for this specific technique.
"single page design" or the synonymous "one page design" is the most useful term to Google for, although it is not the most accurate--the given technique may be used on one page of a site with many pages, and there are plenty of simple one-page sites that do not use any of the techniques commonly discussed in "single page design". Even many sites lauded as great examples of single page design do not use this technique, but it's the closest term.
"long page design" is more accurate, but not as frequently used. In either case, this technique is a subset of that; if this technique is used, it's going to be a part of a long page, but not all long pages use this technique.
I personally like the term "scroll slides," but since I made that up it's not going to be very useful until the day when all the Internet bows to my will. Might be a while.
More terms that came up in the confusion were "infinite scrolling pages" - which is a separate technique, of course and is rarely correlated with this technique - and zebra striping, which may be similar, but is intended to make it easier to pick apart rows packed close together, not visually distinguish huge screen-size chunks.