Hosted, embeddable forum solution?

[David Brewer]

I'm embarking on a research project to find a hosted forum solution
for a client. There seem to be a million of these, and I thought
before digging too deep I'd ask if anywhere here has experience with
and can recommend such a beast.

Ideally, I'm looking for something that:
* allows some simple customization of the appearance of the forum
* supports creating any number of topics
* supports disabling most frivolous features... I just need basic
threaded forum channels, not messaging between users, 5000 emoticons,
or the ability to throw virtual banana cream pies.

In my dream world, this forum would also have a full javascript API
and be easily integrated into an existing site. Something along the
lines of 'just put this javascript/iframe code at the end of your page
to automatically embed a page-specific forum topic' would be
absolutely fantastic.

Thanks in advance for any help. I'll be glad to share the results of
what I find in my research with anyone who is interested.

David Brewer