Modding a TV for RGB may "work", but it's very unlikely to be up to the quality of a stock RGB input unless the modder happens to design monitor chassis professionally. Using a component adapter will definitely work, with the correct levels, and the loss should not be visible, but artifacts may be introduced. Is it worth it over what? S-Video? That depends. Under ideal circumstances most 8 and 16-bit games over S-video won't show improvement with component. High resolution (many many 32-bit+) games however will show a definite improvement with component because S-video severely limits the color bandwidth in these games -> sloppy pixels.
So, i'm kind of stuck. I really don't know which way to follow but I'm starting to believe that a tv with video component is the way to go.
I don't know anything about finding tvs in brazil. My crt accepts 240p component, light guns, and surprisingly famicom rf (channel 95).