A postscript that might give other researchers some ideas:
As mentioned earlier, the surnames Taylor and Lawrence used as middle names in a Paisley Smith family were both family-member maiden surnames.
It turns out that the middle names Allan, Murray, Raeside and Cockburn also had close family connections.
I am amused as to the way in which Allan was used:
Marion Taylor married John Allan in 1863. She had a niece born in 1879 who was named Marion Allan Taylor, and another niece born in 1884 named Marion Allan Taylor Smith.
Thomas Smith had married Janet Lawrence in 1845, but Janet must have died quite young because Thomas also married Margaret Raeside in 1856. Margaret Raeside happened to be the daughter of John Raeside and Janet Murray, so they called a son John Murray Smith in 1862.
One of Thomas' children from his first marriage, William, had a son in 1886, and he was also named John Murray Smith - as were sons in two following Smith generations.
A nephew of William Smith's wife (Mary nee Taylor) married Martha Cokburn in 1884 - William and Mary named their second youngest child Martha Cockburn Smith in 1891.
William and Mary then named their youngest daughter Margaret Raeside Smith, clearly after William's step-mother.
A Ferguson / Taylor family from Paisley who emigrated to the US also gave some of their children strings of family surnames as middle names, so it might well be that others of you will find similar instances.
Happy hunting everybody!
Manui