Really? What were you doing that violated their TOS?

I know it's still possible because there ARE seo's that are using illegal methods...
heard about one the other day where half of the guy's homepage was being
shown at the top of google before his competitor made a call to google.

Anyone blacklisted for REGULAR seo services?

I've noticed that folks never post their urls when this happens?

I mean.. I could just post that 34 of my websites, that I used XYZ seo company for, were blacklisted from such-and-such search engine...
I've actually noticed a lot of postings like that. *shrug*

I'm seriously interested in hearing about people that have been blacklisted and the
history that lead up to that action being taken by the search engines.

lots of sites are blacklisted all the time. common ones

linking out to shady sites
302 redirect errors
people redirecting their penalty at your site
buying too many highly visible off topic links