'52 blackwater tank

[Cruiser]

We're dropping the belly pan of our '52 Cruiser in order to inspect/ repair water damage to the floor. So far it's worse than we'd hoped, but not as bad as it could have been! As long as the bottom is open, we want to install a black water tank (It's a park model w/o holding tanks). I remember 59 Toaster commenting that some of the 50's toilets sat on top of a raised tank, visible in the bathroom. Does anyone know what size these tanks were and how they were installed? Are they still available? We're currently looking at options. The trailer now has a marine head that empties outside the frame rails on the streetside. There doesn't appear to be much room for a tank there. It seems that any tank under the toilet would have to be raised or extend well below the belly pan (or both). A tank between the rails would be neater, but wouldn't be under the toilet (I'm unsure how to route the plumbing to it), and I imagine it would need to be shallow (the frame has a 3" profile). We also wonder about the problems with an exposed tank and freezing. We've admired photos of Levon's installation. Have others tried different solutions?
Doug

[markdoane]

This is probably too late to do you any good, but the "raised" blackwater tank is about 5" tall, and only holds about 5-6 gallons. I have mine removed right now if you still want to see it.