Peter, this is half an answer. If there's a way to send fancily formatted e-mails straight out of FMP, I haven't discovered it.

HOWEVER, it's possible to send fancily formatted ATTACHMENTS, so that's generally what I do, with a few brief lines of plain-vanilla text as a header.

The drawback to this is that, if the attachment contains personalized info (and I mainly work with renewal notices which absolutely DO have to be customized), I have to generate each attachment individually, 1 at a time. For the small-size non-profits I work with, this invariably proves easier than what they HAD been doing, but I wouldn't recommend it for much more than a couple of hundred recipients.