Look what I found on the net, this sounds like even with exercise you cannot really gain much range. :(
Are there physical therapy type of exercises we can do to increase the spread of our short fingers ?
My advice is to avoid stretching exercises like the plague. From experience, you have a certain stretch that your hand is comfortable reaching and you can maybe expand this slightly through exercise ( I emphasis slightly), but I know for a fact that you are more likely to damage your hand. Stretching exercises affect the tendons in the arm and can lead to tendonitis, which I've heard of happening quite frequently and in fact have been very close to having it myself from trying stretching exercises. I was lucky I stopped immediately when I started experiencing, and I've heard of people who couldn't play at all after they had it, so its not worth it, please trust me on this one. You just have to accept the stretch your born with.