I think introducing a new item to the game, something like "Sparkle Stone" to be held by fathers during breeding to double bred shiny chance would be great.
1/8191 to 1/4096 would be nice, and it would still be pretty dang rare, but still introduce some people who've never gotten a legitemate shiny (Exc. Shiny Gyrados in Lake of Rage or Island ticket for Shiny Lat@s.) could possibly find one.
I myself have only found a couple.
--Shiny Krabby in Crystal (Loved him, he was pretty good and was in my final team. I just wish I had held onto that cartridge. Hopefully I'll get another Shiny Kingler to use someday.)
--Shiny Wailmer in Sapphire (Loved her, but I never really used her, because unluckily she had VERY bad IVs and she wasn't that useful to a part of my team for me, sadly as Milotic took her place. I still loved Water Spout, it was one heck of a Water Type attack.)
--Shiny Spinda in Emerald (In all seriousness, I was sorely dissapointed. This Pokemon is absolutely NO GOOD. not only did its IVs suck when I got him, his base stats also suck (60 in all stats) and his only good move was Dizzy Punch and Teeter Dance was marginally good in some situations. Nonetheless, I liked her, but I just never trained her past 47. Maybe if Spinda gets an evolution will I use her... Just maybe...)