I went in one of the New Balance shops up in the Lake district a couple of weeks back, the one in Keswick. Anyway, one of guys phoned the head office for me & basically said that all, bar one, of the trainers they had in the shop were made from synthetic materials.
Now, i know that doesn't necesarily mean they are all vegan (maybe the glue they use might be an issue???), but they do still have the 'vegan friendly' logo on the website.
Got a pair when i went anyway. £50 reduced from £75. Can't remember what the number is though.
Also, a girl who works at the shop in Keswick is vegan, but she wasn't there when i went.