I think you could. Check with Wirsbo out of Minnesota. They will provide you with complete details for a design.
The key is to run 4 zones. Split the garage into 4 parts, drawing a cross through the center of the garage. Each quarter is one zone. Each zone begins at the manifold, travels to the outside wall and runs in 6" loops along the outside wall working its way to the inside center of the garage, then heads back to the manifold. All 8 pipes travel up the center line before branching out to loop in the appropriate zone. You need to insulate on top of the dirt and below the concrete. There are Horseshoe hooks that hold the pipe in place suspended in the concrete, or you can zip tie it to the wire mesh, as long as you make sure the concrete guys pull the mesh up into the concrete.
The hardest part is the work with the boiler. You probably need a professional to set the boiler. Bring all the pipes up at least 2' above the concrete and attach them to a 2x4 until after the concrete is poured. Make sure you label supply and return lines, or you will have a big mess.