I don't think so. The tanks (at least in my unit) are installed whilst the frame is flipped on the line. Then the pans are installed. So when the frame assembly is flipped right side up, the tanks are just sitting in the pan.
I have struggled with the same issue, as I would like to finesse the heat ducts and insulation. I have a couple of accesses through the floor, but I don't think its enough to somehow support the tanks adequately from above with cords, temp brackets, etc.
I'm afraid all the plumbing would have to be disconnected, and drop the whole assembly.