I've put together a test package of Portable SciTE. SciTE is a solid text editor that is actually quite portable by default. In the portable package I put together, I've compressed it with UPX, setup the standard App/Data directory structures so things are easier to backup and upgrade, and changed some configuration options that I think are appropriate for our use (toolbar/status bar visible, line numbers enabled, NSIS support enabled, status bar layout changed to include all necessary details). All the config changes were made in the SciTEUser.properties file, so you can easily revert to a base SciTE config by deleting that file... or drop in your own file from your local copy so your portable copy will work the same way.
It's a 1.1MB install, 770KB download:
Please let me know what you think.