Ah. Sorry for the misunderstanding, John.
Trois Pistoles from Unibroue has lovely yeast and is dark. It's not that bitter, though.
Any number of Russian Imperial Stouts - North Coast, Victory, Stone, Bell's.
I ought not neglect a relatively new and evolving style - black IPA or "Cascade Dark Ale" - Good examples from Deschutes (Hop in the Dark) and Full Sail (Bump in the Night), among others. The Yakima Glory from Victory is really nice (as are all their beers). It is an interesting style, since the bitterness comes from both hops and roasted malt. I'm not sure I'd really characterize them as "yeasty", though. Perhaps if dispensed live instead of bottled.
bibere usque ad hilaritatem