It depends on the page thickness and typestyle used. I've got a Latin copy in one small (missal-sized) volume.
University of Chicago's Great Book series put the entire Summa into two volumes.
The Blackfriars/McGraw Hill did publish the Summa as a 61-volume set on thick, acid-free paper between 1964 - 1975 (wide margins and large font, too). This series was bilingual, with the Latin text and English translations facing each other, both sets with copious footnotes and endnotes. But that was well after Sheen's "Life is Worth Living" program. So I don't know what books you saw on Bishop Sheen's shelf, but I doubt it was the Summa. It's not all that long -- you have to work to stretch it out with a lot of annotations.
The Omnia Opera of St. Thomas Aquinas has been published as 25 volume (Marietti) and 33 volume (Musurgia) sets.
By the way, Cambridge University Press is re-publishing the bilingual Blackfriars' editon -- I highly recommend it, but it is pricey. (052169048X / 9780521690485)