The Collaborative International Dictionary of English v.0.48:

Sightly \Sight"ly\, a.
   1. Pleasing to the sight; comely. "Many brave, sightly
      horses." --L'Estrange.
      [1913 Webster]

   2. Open to sight; conspicuous; as, a house stands in a
      sightly place.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sightly
    adj 1: very pleasing to the eye; "my bonny lass"; "there's a
           bonny bay beyond"; "a comely face"; "young fair maidens"
           [syn: bonny, bonnie, comely, fair, sightly]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "sightly":
   Junoesque, agreeable, amply endowed, becoming, bonny, braw, built,
   built for comfort, buxom, callipygian, callipygous, comely,
   curvaceous, curvy, fair, goddess-like, good-looking, goodly,
   likely, lovely to behold, personable, pleasing, pneumatic,
   presentable, shapely, slender, stacked, statuesque, well-built,
   well-favored, well-formed, well-made, well-proportioned,
   well-shaped, well-stacked