You can use a Transcoder on about any card. Any of the X800pro/XT cards ship with YPbPr out (I'm assuming what you mean). AIW 9700/9800pro cards have it in the box, and most 8500+ Radeon's will support the adaptor from ATI. Personal Cinema 5700 cards have YPbPr on the breakout box, MyVIVO 5950 ultra cards from Leadtek IIRC.
I think some of the new cards like 6600 and some X700 cards as well. Take your pick on the performance you want, theres's either a model that supports it natively or add a transcoder.