You can buy mobile home aluminum rolled roofing from All-Rite Aluminum at www.all-rite.com
They are in Holister CA, but ship everywhere through their web site. If this is a large piece, you want the seamed aluminum roof. The stuff is pricey when sold retail. You could also check with your local RV repair shops. All-Rite supplies all of the repair shops and RV super store places. Whoever is supplying the the shops near you with RV aluminum siding, doors, hatches etc. would probably also have mobile home roof material. You can probably order locally and save some money.
All-Rite also has the diamond pattern in aluminum, but I doubt that it is thick enough or wide enough for use on mobile home roofs.