To keep on working, I found Cream (http://cream.sourceforge.net). This editor is free and handles fairly well files of larger dimension. It is supported across multiple Operative Systems, I could use VIM but I really prefer to use big round buttons and menus to get my work done.
Albeit the cream editor allows you to change big files, it is not a magic bullet and you should be prepared to wait some time until your changes are saved back to the file on disk.
Having said this, I think the tool is really worth to try out.