There probably aren't very many animals that can be used for fermenting. most mammal blood really isn't very sweet at all and doesn't contain much in the way of convertible carbohydrates. I expect that the presence of large amounts or protein and iron would also foul stuff up pretty badly if you tried to fortify the blood with sugar.
If you did come up with blood with high enough sugar content to support fermentation you could probably cook it a bit to get the protein to curdle out then strain and possibly reduce the remaining liquid to increase its sugar content.
The only animals I can think of right off the bat that could be expected to have very sweet blood are quite small and there would be significant obstacles to collecting a sufficient number of them, hummingbirds, sugar gliders (sugar gliders have extremely sugary urine as well if you're also thinking about piss wine) and common wood frogs during hibernation.
Of those I'd pick hibernating wood frogs as your most likely, they aren't particularly rare and they hibernate frozen solid with their blood turned to glucose syrup.
Besides frog blood wine sounds significantly more badass than hummingbird blood wine... and they are less likely to fly away when you are truing to catch them.
I can see it now... frog pickers roaming the winter forest with their trusty frog sniffing dogs (froghounds) and a five gallon pail filling up with frozen frogs.
I imagine you'd grind them whole and mash them with just enough water to rinse the sugar out of the cooked frog bits, you might want to break the glucose with a naturally occurring enzyme for the sake of authenticity... and you're away to the races.
"a woman who drives you to drink is hard to find, most of them will make you drive yourself."
anon--
. At that point I took the bottle away from him and he still will not shut up about it. He says that the cows blood over in the korean market they sell by the gallon could be turned to wine if I just diluted it and added sugar and yeast I told him there is no way in hell I will ever be doing that and then he said that he could just do it himself 
I managed to talk him out of it with the image of how his wife will react and started him off with a nice fail proof apple wine. Props to him for getting some home brewing inspiration, but if blood wine is what he starts out with I think I'm going to keep an eye out for him 
Not that it is not fun but 
