There are quite a few historic sermons on this portion of Scripture:
15:21-22
Rutherford, Samuel, "The Trial and Triumph of Faith," (sermons 1-10), Naphtali Press Anthology, vol. 2, no. 4, Fall 1989, pp. 40-66, 96.
15:23-25
Rutherford, Samuel, "The Trial and Triumph of Faith," (sermons 11-18), Naphtali Press Anthology, vol. 3, no. 1, Winter 1990, pp. 61-90.
15:24-25
Spurgeon, C.H., "How to Meet the Doctrine of Election," #1797, MTP 30.469-480.
15:26-27
Spurgeon, C.H., "The Little Dogs," (together with the text of Mk 7:27-28), #1309, MTP 22.457-468.
15:27
Guthrie, William, in two sermons, untitled, Sermons Delivered in Times of Persecution in Scotland, pp. 215-225 and 226-236.
Spurgeon, C.H., "Children's Bread Given to Dogs," #715, MTP 12.565-576.
Spurgeon, C.H., "Pleading, Not Contradiction," #2129, MTP 36.85-96.
15:28
Guthrie, William, untitled, Sermons Delivered in Times of Persecution in Scotland, pp. 237-252. The editor notes at the end of this sermon that "There is another sermon upon this text, wherein Mr. Guthrie begins upon the third particular here not spoken to, viz., church deliverance."
Spurgeon, C.H., "Little Faith and Great Faith," - see entry above at 14:31.
Spurgeon, C.H., "The Perseverance of Faith," #2253, MTP 38.193-201. With attached expostion of Mt 15:21-39, on pp. 202-204.
Spurgeon, C.H., "Carte-Blanche," #2446, MTP 42.1-10.
From:
http://pcahistory.org/sermons/mt.html
And don't forget about Calvin's
Commentary on a Harmony of the Evangelists, v.2, pp.262ff, or John Lightfoot's
A Commentary On the New Testament from the Talmud and Hebraica, v.2,
in loc.