I totally understand what your thinking.
Here's what I was thinkin...
A bulkhead is a big, tedious job. Floorpans are reletively easy. It makes sense to change pans, but finding a pan that doesn't have rusty floors may be a challenge, and finding one with a solid bulkhead and rusty pan halves shouldn't be too hard. If the body is going to be off the pan (which of course it would be) pan halves are an easy rust repair job to tackle. I hope I make sense, it sounds logical in my head but I usually have a hard time typing my thoughts.