In doing some digging into the history of Calvin's Commentaries, I came across a complete pdf of Calvin: Commentaries The Library of Christian Classics Volume XXIII. The library of Christian Classics is a 26 volume set put out by Westminster John Knox Press, Presbyterian Publishing.
I came across this complete pdf while searching for more contemporary translations of Calvin's Commentaries. Some of the free versions of Calvin's Commentaries are of a style that the translators of this volume state "is no longer our own." And also:
"The older translations are from the hands of a number of scholars. Their English styles are different, and not of the same quality. Besides, the exegetical and theological predilections of the several translators have understandably colored their versions of the Latin text."
This volume was included in the massive The Calvin 500 Collection from Logos.
Addendum
The old versions of Calvin's Commentaries are based on Calvin's Latin and French versions. The Latin versions were taken from the Corpus Reformatorum. This appears to be a link to a good chunk of the the Corpus Reformatorum.
Joannis Calvini opera quae supersunt omnia
Author
Calvin, Jean
Editors
Cunitz, Edouard
Baum, Johann-Wilhelm
Reuss, Eduard Wilhelm Eugen
PublicationBrunsvigae: C.A. Schwetschke, 1863CollectionCorpus reformatorum
Description59 tomes en 58 vol. : ill. ; 27 cmNoteTomes parus entre 1863 et 1900Stable URLhttp://archive-ouverte.unige.ch/unige:650Structures
Faculté autonome de théologie protestante
Full text
Index général (799 Kb) - 
Free access
Index lettres (4.1 MB) - Free access
Tome 1 (72.9 MB) - Free access
Tome 2 (120.8 MB) - Free access
Tome 3 (37.5 MB) - Free access
Tome 4 (71.5 MB) - Free access
Tome 5 (39.5 MB) - Free access
Tome 6 (32.5 MB) - Free access
Tome 7 (41.5 MB) - Free access
Tome 8 (46.1 MB) - Free access
Tome 9 (47.5 MB) - Free access
Tome 10 (39.5 MB) - Free access
Tome 11 (42.2 MB) - Free access
Tome 12 (36.3 MB) - Free access
Tome 13 (33.8 MB) - Free access
Tome 14 (36.6 MB) - Free access
Tome 15 (45 MB) - Free access
Tome 16 (37.8 MB) - Free access
Tome 17 (36.3 MB) - Free access
Tome 18 (39 MB) - Free access
Tome 19 (36 MB) - Free access
Tome 20 (33.8 MB) - Free access
Tome 21 (38 MB) - Free access
Tome 22 (19.2 MB) - Free access
Tome 23 (45.9 MB) - Free access
Tome 24 (40.3 MB) - Free access
Tome 25 (39.4 MB) - Free access
Tome 26 (41 MB) - Free access
Tome 27 (38.6 MB) - Free access
Tome 28 (40.3 MB) - Free access
Tome 29 (40.6 MB) - Free access
Tome 30 (45.7 MB) - Free access
Tome 31 (46.1 MB) - Free access
Tome 32 (40.3 MB) - Free access
Tome 33 (40.6 MB) - Free access
Tome 34 (38.3 MB) - Free access
Tome 35 (36 MB) - Free access
Tome 36 (58.8 MB) - Free access
Tome 37 (42.3 MB) - Free access
Tome 38 (39.4 MB) - Free access
Tome 39 (35.5 MB) - Free access
Tome 40 (39.6 MB) - Free access
Tome 41 (41.6 MB) - Free access
Tome 42 (47.1 MB) - Free access
Tome 43 (35.7 MB) - Free access
Tome 44 (27.7 MB) - Free access
Tome 45 (46.6 MB) - Free access
Tome 46 (52.1 MB) - Free access
Tome 47 (27.7 MB) - Free access
Tome 48 (37.6 MB) - Free access
Tome 49 (46.8 MB) - Free access
Tome 50 (37.4 MB) - Free access
Tome 51 (45.7 MB) - Free access
Tome 52 (21.8 MB) - Free access
Tome 53 (36 MB) - Free access
Tome 54 (30.7 MB) - Free access
Tome 55 (35.8 MB) - Free access
Tome 56 (33.7 MB) - Free access
Tome 57 (25.8 MB) - Free access
Tome 58 / 59 (54.9 MB) - Free access
Many of these volumes are also available here:
CR 29; Opp,
CR 30; Opp. 2 - 1864
CR 31; Opp. 3 - 1865
CR 32; Opp.
CR 33; Opp.
CR 34; Opp. 6 - 1867
CR 35; Opp. 7 - 1868
CR 37; Opp. 9 - 1870
CR 38; Opp. 10 (Pars Prior. & Pars Posterior.) - 1871 & 1872
CR 39; Opp.
CR 40; Opp.
CR 41; Opp.
CR 42; Opp.
CR 43; Opp.
CR 44; Opp. 16 - 1877
CR 45; Opp.
CR 46; Opp.
CR 47; Opp.
CR 48; Opp.
CR 49; Opp. 21 - 1879
CR 50; Opp. 22 - 1880
CR 51; Opp.
CR 52; Opp.
CR 53; Opp.
CR 54; Opp.
CR 55; Opp.
CR 56; Opp.
CR 57; Opp.
CR 58; Opp.
CR 59; Opp.31 –1887
CR 60; Opp.32 – 1887
CR 61; Opp.33 – 1887
CR 62; Opp.34 –1887
CR 63; Opp.35 – 1887
CR 64; Opp.36 –1888
CR 65; Opp.37 – 1888
CR 66; Opp.38 – 1888
CR 67; Opp.
CR 68; Opp.
CR 69; Opp.
CR 70; Opp.
CR 71; Opp.43 – 1890
CR 72; Opp.44 -1890
CR 73; Opp.45 – 1891
CR 74; Opp.46 –1891
CR 75; Opp.
CR 76; Opp.
CR 77; Opp.
CR 78; Opp.
CR 79; Opp.51 – 1895
CR 80; Opp.52 – 1895
CR 81; Opp.53 – 1895
CR 82; Opp.54 – 1895
CR 83; Opp.55 – 1896
CR 84; Opp.
CR 85; Opp.57 –1897
CR 86-87; Opp.58-19 – 1900