That has already been done and a company marketed it.
The problem with that was the fact that the *istDS/DL/DS2/DL2 and K110/100/100D super (same body) has no bottom contacts and once you consider that, the battery cover would be in the way (you have to open or do away with the battery cover to provide contact for the grip).
If you want to take the alternate route though and go by the DC connection port by the side of the camera, then you have to expose all of the connection ports since you will have that door open for the DC connection.
Anyway, here is one of those battery (I mean no battery as it is just a vertical grip) grips in production.
Review of the Dicain Vertical Shutter Grip for K100D & Super
This is the third variant if I'm not mistaken.
There was another one that was a real battery grip but then the battery cover had to be open and it didn't provide any vertical camera controls as the connection ports are on the side of the camera.
There is also the Ownuser battery grip but all the wire connections are exposed by the side of the camera:
Ownuser Battery Grip Review
I wanted something similar before but then I guess, the "AA's" work just fine!
