You would only consider a shepherdess for a large number of lambs, surely?
Firstly it wouldn't be cost-effective for 2-3 lambs, and secondly I can't quite get my head around how it would work when it's only being required to deliver say a gallon of milk over a 24 hour period.
However, I've never used one, so perhaps those who have will be able to make more intelligent and constructive comment!
I shall watch with interest; we knew we would end up with a significant number of pet lambs this year and I am already on 16, with only one of those looking likely to die. There will be more yet, and the oldest batch are only 3-4 weeks old (and I like to wean no earlier than 6 weeks, preferably at about 7 weeks), so I am pondering mass-delivery systems and possibly a single cluster milking machine for the Jerseys.