The contacts can be removed from the shell for the front panel connectors and the contacts from the LL connectors put in to suit or you can use what comes on the LL. The bigger problem is that they make custom drawer fronts and bezels for the optical drives, but if yours happen to be generic then you can use them otherwise they won't have any fronts on them - not good for opticals. And the I/O ports arrangement on the back of the mobo may not fit a standard I/O shield and the one in the Dell case may not be transferable to the new case as it may not be a separate piece. But I've heard that Dell has gone with a lot more standard stuff to shorten product cycle times and the expense of customized parts.
From the pix I just looked at, it shouldn't be too difficult - they use generic optical drives and it looks like the I/O shield is removable and about standard dimensions. It does have a proprietary CPU cooling solution, but looks like it wouldn't be too hard to mod for use in a std. case.
.bh.