You won't need glossy paper actually, once they're in the cases themselves they'll look fine next to official ones, assuming you use a good printer. I'd just go for a nice matte paper, it dries a lot faster anyhow. Nobody will tell unless they start taking covers out of their cases.
You don't need legal sized for DVD covers, there's a simple workaround to get them to fit on regular paper. Simply use page setup, set the paper type to legal, orientation to horizontal, disable vertical/horizontal centering, and set the margins as small as they can go. Your printer will act as if it's printing on legal sized paper even though it's using standard sized, and the cover should fit fine on it. I've done this myself many, many times with fine results.