A follow-up on the extreme sheep art story is here:
http://news.bbc.co.uk/1/hi/wales/7961889.stm
There's an interview with the shepherd artists.
'A group of shepherds talk to Penny Roberts about the challenges of making an 'extreme shepherding' internet advertisement for Samsung and YouTube. The viral advert on site YouTube has already had thousands of viewers. The shepherds claim it was "good dogs and good sheep", not computer trickery.'