I guess I should clarify. We use MDT to create our reference image on a VM with a 40GB disk. During the MDT deploy task we apply all of the windows updates. If we are making a fat image then we install the additional software at that time (using a fat image task sequence in MDT). When we have the image the way we want it, then we sysprep it and capture the image. At this capture point we still only have a 40GB disk. So we deploy that 40GB disk to the target computer and then once on the target computer we extend the disk with diskpart.
We do it this way because we rebuild the golden image each quarter. If you have everything setup to create your reference image automatically, the actual hands on time is very small. What takes the most time from start to finish is windows updates. So far with the WIndows 7 updates it takes overnight to apply them all (~14 hrs).
While I got a bit off point, the key is to deploy a smaller image to your client computers than their smallest disk size then extend their logical disk to the physical size during the cleanup process.
