Another possibility: Mitsubishi Microcontrollers makes an OSD chip, M35060-xxxSP. This is a parallel port interface type of part, rather than serial. And unfortunately, Mitsubishi doesn't sell them in the States, but you can get them if you want to buy 50,000 of them, and don't want any tech support. A potential distributor is AllAmerican: http://www.allamerican.com/

The more people that ask them about the part the more likely they'll buy the 50K parts.