is the study done by people at the University of Pennsylvania:
Journal of the American Veterinary Medical Association
July 1, 2006, Vol. 229, No. 1, Pages 70-73
One manufacturer in Australia had their products evaluated: http://veganpet.com.au/articles/?page_id=10
depends a lot on anecdotes for some stuff, which I don't like, but it did collect a lot of information. With the knowledge void, I understand that anecdotes and extrapolation are sometimes all that's available.
Obligate Carnivore by Jed Gillen has some inaccurate information but I liked the views on the effects of veganism and the advice for switching over animals to new foods. I personally wouldn't let a cat go over 12 hours or so refusing food as I'm afraid of organ failure (and I think it's mean to starve someone into accepting a food that tastes too strange or unpleasant). At one shelter I volunteered at, the cat employee told me she'd lost cats who were so stressed they wouldn't eat. I went around with her as she forcefed cats so that wouldn't happen again.
are galleries of cats and dogs who eat vegetarian food, including cats who were vegan for 10+ years. Some people like personal stories like that. I thought http://www.vegepet.com/Stories/twokittens.html
was very cute
The earliest commercial product for vegan cat diets is Vegecat from 1986, to my knowledge, followed by Evolution from 1989.
I hope this is helpful.