For that case? They probably AREN'T available. That's a pretty old Ultra model and the front panel USB port harness is likely proprietary. You might be able to make something universal work but I wouldn't count on it without some experience in case or electronics modifications.
You would be a lot better off, much less expensive and much more likely to be happy with the end result if you simply purchased a USB hub with a decently long cable. Plus you'd end up with more USB ports than you would with the case.
You could try contacting Ultra about a replacement front panel USB harness but I would not hold my breath. Ultra is a world class crap company to deal with, that generally makes world class crap parts as well. Might even be better off simply looking at replacement cases.