Shortening the bow is really not an option. The limb design is a function of the length, the core materials that make it up, and the width of the limbs. Shortening the bow, especially that much, would make it dramatically heavier and completely change the shooting characteristics.
Changing the grip to fit your preference would be a fairly simple modification though, so if you could live with the longer length if the grip fit better that would be a good route to go. To me, grip is everything in a bow, and if one fits you it makes all the difference in the world. And personally, I prefer longer bows over shorter ones. They are more forgiving and smoother drawing. (At least in my mind)
If you really want a short bow, your best bet is to take your lumps and sell your bow and then use that money toward the bow of your dreams. A trade might work if you can find someone who wants exactly what you have and he happens to have exactly what you want. But that is much harder to pull off than a sale/purchase transaction.
Good luck!