I don't know that you can find a rollpan already pre made for an explorer yet. They don't make them. You can see if you can get a Ranger rollpan to work, but it will take some fiberglass work....I don't know how much really though. I think people who have made there own rollpans have usually used an f150 rollpan and cut it down then did the fiberglass work to make it fit and blend in. You also have to cut the frame and you can't use the spare tire carrier anymore when you do that.
I have no experince in doing a rollpan but I have SEARCHED around and that is some of the info I have found out about a rollpan and explorers. Hope it helps. Welcome to the site!