I totally agree with jmaat7.. I also have xampp and eclipse on a flashdrive.. I even have the static ffmpeg to work with the ffmpeg-php in my thumb drive.
My portable eclipse is a portable eclipse php version can be downloaded by Clicking Here. I saved about 50MB of space..
It is working pretty well without any issues, but if you will be working on smarty templating system, make sure to ignore the errors and warnings being caught by the eclipse from the template directory. Portable eclipse just don't have the extra module to recognize the smarty syntax. To correct this problem you may want to mock up smartypdt with the eclipse installation as you see it fit.