Topeak Explorer 29er Tubular Rack
Topeak's Explorer 29er Tubular Rack is a great add-on for carrying a trunk bag, pannier or anything else you want to strap onto your big-wheeled bike. It's made of tubular aluminum, fits most bikes, holds up to 55 pounds and has a center strip that acts like a short fender. It's compatible with Topeak's QuickTrack bags and accessories (sold separately), too.
QuickTrack mounting overview