Well, as far as the video card questions...
http://www.arcadecontrols.org/yabbse/index.php?board=1;action=display;threadid=3012No, they are not that expensive, and yes, there are many cards (some in that thread) that use RCA only jacks,, but don't plan on reading a book on that mother as text would just be impossible to read. So, it's not NEEDED, and alot of people run them that way, the picture is just not going to be that sharp. Even with an S-Video out, if you ran windows on the TV, the text would be very hard to read, and RCA is one step below that. But hey, during a heated game of Marvel VS Capcom, you hardly notice a difference. Like I said, the only complaints I have heard is that the windows text is hard to read, I'm sure if your not whiny, and just want to play games for cheap on a tv or arcade cabinet with a tv in it, it works fine, it's not like it's going to hinder your playing and whatnot, just look not as sharp as S-Video.
you can tell the difference between a Geo Metro and a Covette , but they both get you where you are going.
Hope that was any help.