Like TiddlySpace we want to be able to augment a tank with custom JavaScript and CSS. An option for doing this is to do it exactly like TiddlySpace, but improve the filenames:
The mechanism would be effectively the same, but it would be ideal if adding to the tiddlers had tools rather than just by hand editing. One way to do this would be for tanks to self identify as commands which packaging. That is, if a tank had a command.css or command.js then it would present its index page with an "I am a command, use me" thingie.