embedding image in a larger array?

We would like to embed the experimental camera image into a larger array. We would like to do this for two reasons:

1) To provide margin for image shifts so that the camera image does not intrude on itself (cyclic copy) when shifted.

2) To speed up FFT by using power of 2 algorithm.

For the K2 camera, this would be a 4096 x 4096 image for normal resolution and 8192 x 8192 for super-resolution.

I have problems finding the right routines for doing this in cistem. Such an extension would definitely be useful, if it doesn't already exist in the code. How should I proceed?

This work is being done in the lab of Zbyszek Otwinowski. He discussed the subject already with some developers at the recent Lake Tahoe meeting.