Nev: I hadn't really thought about these in a one-shot or convention environment. As discussed a few posts up, you'd want a different reward scheme, since experience points aren't terribly important in that situation. But it could certainly be fun--turn the traditionally on-rails feel of a convention D&D adventure on its ear! Maybe pare down the deck, too, take out things with a long-term focus like some of the faction-related cards.
unan: I've been using these in my current game, which is two sessions into 5th level. Some of the cards were added later than others, based on feedback and the maturation of the idea. For instance, I initially had cards to override skill checks only for the knowledge skills, but I expanded it to have one such card for every skill. Illustrations I hadn't thought of! I bet some cute stuff could be done with that, but I'm no artist. As for formatting...
doug: I don't have such a file yet; I was planning to create one after getting some feedback, see if anybody came up with more card ideas. If you're volunteering, though, go for it! That'd be a fantastic help.