I think there is a big misunderstanding about this thread. XLISP, CommonLisp, Scheme, etc. are not development environments; they are languages. They are programs to read a filetype. Just like AutoCAD is a ".DWG intrepeter", XLISP would be a ".LSP interpreter". If you want a `development environment' for .lsp files you can have your pick of a thousand different text editors.
If I can draw on that analogy a bit more:
If you did not have AutoCAD on your machine, if you double clicked on a .DWG file nothing would happen. AutoCAD is the program that reads .DWG files. As we all know .DWG files do not do anything but imagine if you double clicked a ".lsp" file and stuff happened like when you double click a ".BAT" file. That is what XLISP, CommonLisp, etc. is. It is not a `development environment`, you type up files (like you draw .dwg files) in a text editor and send those files to a program like XLISP, CommonLisp, Scheme, etc interpreter. It then knows how to do stuff based on your instructions written in Lisp. Your instructions can be anything you want; you are, currently, only used to writing lisp instructions to operate in a small environment (AutoCAD, blocks, layers, etc) where as, with an interpreter like this, your environment would then be the computer.
If none of that makes sense, I'm sorry but, this thread may not be for you.
If you don't want to make/change/add/delete/download files on your computer using Lisp then this thread may not be for you.
If you don't want to create a "bank account program" or "address book program" or "goo-gah widget program" then this thread isn't for you.