It's outside my budget right now, but some of you might be interested to know that Loome Books has the following for sale:
BYRNES, AQUINAS, O.P. (Editor). The Hymns of the Dominican Missal and Breviary. St. Louis, London: Herder, 1943. 8vo, xi + 694pp. Bound in original black cloth, gilt title to spine. Edges red. Fine condition.
Price: $85.00
This particular book presents all of the hymn texts found in the Missale and Breviarium S.O.P. and gives them in parallel Latin and English translation.
The book also includes much footnoting that looks at the scriptural and liturgical origins of the hymns.
Titles like this aren't, of course, typically very readily available.