I've tried several cases thus far, and none seem to fit correctly, they are all either slightly too large or just barely too small to fit my 5th generation 30gb iPod video; I have modified it, and replaced the entire housing with a new one recently, modifications include a new battery & 256gb SSD.
So far I have tried these two cases:
Both of which came with 2 size backshells one which was a hair too small, and the other of which was 2-3mm too large, leaving a gap begging for debris to get caught in.
I'd prefer a hard case, as the sticky feel of most rubber cases is very irritating to me, especially since I generally toss my iPod in my pocket and the silicone loves to grip the pocket, and any lint that has managed to stick around. I am however, all ears to any outstanding soft cases as well.