The article posted by thanmuwa makes a very interesting point about Aran Sweaters:

Contrary to popular belief, the typical cable-patterned Aran jumper is a 20th-century invention. In 1891 the government set up the Congested Districts Board to help poor families to survive unemployment and a shortage of potatoes. The Board encouraged local people to weave and knit garments to sell.

By the 20th century this cottage industry began to take off and the Board trained knitters to create complex patterns from stitches such as honeycomb, figure eight and double diamond. Instead of the dark coloured, oiled wools traditionally used to make fishermen’s jerseys, the islanders experimented with soft, thick, undyed yarn.

By the 1930s, Aran knitting was being sold to tourists from shops in cities like Dublin and it soon became known worldwide. Vogue Knitting published an Aran pattern in 1956 and the design became popular in America. Aran knitting can now be done by machine, but hand-knitted jumpers are still sought after.
I also note that it says nothing about a historical precedent for sweater patterns associated with particular surnames, only regional variations.

Interesting article; thanks for posting!

Regards,

Todd