Anyway, what I'm really curious about is how others around here handle this situation. The most optimal solution, from a development standpoint, is for them to let us know whenever they need something like this, give us the embed code, and we'll tweak the theme/plugin to support it. I'm tempted, at times, to allow the user to add JS in some form to make it easy for them to add stuff like that. I'm conflicted though, between my desire to help them run a fast, secure site, versus my desire to give them a CMS they feel like they have total control over.
Thanks for your thoughts!