Using OpenType glyph substitutions it would be possible to make different forms of the letter e (for example) follow on from different letters. It would not be possible AFAIK to make random glyphs appear. Only a few programs like InDesign support OpenType features, so it is a moot point whether it is worth adding OpenType features. It is not terribly difficult to do, but requires some patience.
See the FontCreator Tutorial section: Adding OpenType Features.
FontCreator cannot do it yet. I wonder if it is worth the development time to add GSUB support? Perhaps not until OpenOffice or other free or budget priced software supports OpenType.