Nice. I managed to find 3 shinies in FireRed journey before I reached the Elite Four, one of them was even from the Safari Zone. I also had the luck to find another shiny in Pearl's Great Marsh and a shiny Graveler in SoulSilver and caught them both. So far, the only shinies I've came across that I haven't caught were rentals from Stadium 2 and Battle Evolution and those 3 I did find were all interestingly Steel-type.
To those low on luck who must absolutely want to encounter a shiny, USUM's Ultra Space is good for that, even if the Pokémon selection is limited.