O well, isnt 4 (including a Rayquaza!) enough lol? Ive seen 2 caught one, thats with over 600 hours of gameplay. Anyhow, I made this up the other day. I call it the Essential Shiny Hunter's Survival Kit (tm). To be prepared for any shiny situation, I recommend this setup:
1. A pokemon in your team that knows False Swipe and Spore. Parasect fits this category, but if you dont wish to use one, the next best combo would be Breloom and Scizor.
2. A pokemon in your team with Suction Cups. The only one I know that most ppl would have access to is Cradily. (Octillery can work if you have one, plus he learns many nice moves.) This is for Roarers and Whirlwinders. (Spore with your lead first, then switch if it is one of those annoying pokes).
3. 50 (30 if youre poor) Ultra Balls (or as many as you can afford). For shinies you havent caught the normal version of before.
4. 50 (30 if youre poor) Repeat Balls. I believe they are found in Rustboro city in Ruby/Sapphire, and on Two Island in FR/LG. Repeat Balls are youre best friend. They work extrememly well on pokemon you have already caught, with most weak ones not even needing to be damaged.
There, happy hunting!