Thanks, the saving the dev environment part was the part that scared me. It certainly helps to have someone tell you you're not crazy. Maybe I'll give it another try sometime!
One of the things I've learned with powerful tools is that, by their nature, they empower you to do bad things almost as much as they empower you to do good things.
It's even alluded to in the ruby bare-words example in this famous talk[1]
Nothing to worry about. Yes, the minimal executable you get with SBCL is a bit fat, but for any real-world application which do some actual work, the size is a non-issue. Especially, as the executables are starting up very fast, as no dynamic linking is necessary, most of the code are static references.
For any sizable Lisp project you would have an ASDF-file to load the system, with that you can create an easy build-script or even a make-file, which loads your program via ASDF and then builds the executable, it is described well here: https://stackoverflow.com/questions/14171849/compiling-commo...
For consistancy, I would recommend to build the executable from the freshly loaded source, not a lisp image which has been used to develop in.