Trotters Dea Slingback

Price Range: $

At Zappos.com:
Rating: 4 out of 5 stars – 846 ratings
Includes many 5 star reviews from narrow buyers, a few of whom mentioned needing to go up a 1/2 size.
Also includes a few reviews from narrow buyers who said the narrow width ran too narrow and too small (but one of these reviewers said the medium width was a good fit), and a review from a narrow buyer who said the shoe lacked adequate toe room and cushioning.
Includes a few 5 star reviews from slim width buyers, and a review from a slim width buyer who said the slim width was not slim enough.
Available in narrow and slim widths.
View shoe on Zappos site

At Nordstrom:
Rating: 4.3 out of 5 stars – 64 ratings
Includes several 5 star reviews from narrow and slim width buyers.
Nordstrom includes a note that the majority of reviews say the shoe runs true to size, but in the size drop down, Nordstrom recommends ordering 1/2 size up.
View shoe on Nordstrom site