These are the ones I've found and penned. The two grays is a question mark, I found one but not sure which one it was before I accidentally killed him (flew with him on lead and he must had fallen off).
This area is FANTASTIC for anyone who wants a major headstart on breeding all of the ponies. :3 I also had found a nice imgur list that details the differences between the white/white horses and couple of the black ones while I used this image from minecraft wikia to check them off.
http://imgur.com/a/2AFtq
This is the seed and the coordinates for anyone who is interested in having a nice collection of ponies. The spawn point of the world is terrific too, the desert had 2 neighboring villages, and 3 desert temples for you to loot.
7169463133465677 and the coordinates for the Equestrian lands is at -14, 69, 5467 and they should be all around you.
EDIT: I apparently had found the Paint flaxen chestnut. (Blonde brown pony with white paint.) Just need to mark that off too.
Double EDIT: Strangely I got two new grays from other colored (no white) breeds somehow. So it wouldn't hurt to just try to get them all to breed. You never know. :3