The lack of stability is frustrating, but a natural aspect of a newly introduced concept. That stability won't be attained until the majority of weak short-term speculators have been knocked out.
I don't think the instability is caused by speculators. They are merely a symptom of the not-yet-stable currency. True stability will naturally occur when there are enough products and services to buy for bitcoins at stable prices.
Your idea is nice, but segregating the service introduces additional maintenance. It doesn't make sense to expend additional resources to maintain a duplicate site. You'll also be spending extreme effort trying to convince thousands of businesses, one at a time.
Well, the idea of having a duplicate site was from Phinnaeus Gage - it is not my main idea, although I think it is a good idea when the resources to do it are available (and with a powerful CMS, the effort will not be big).
My idea is that instead of having volatile BTC prices based on daily exchange rates, businesses should keep their BTC prices fixed, and instead limit the amount of transactions they do using BTC if they need to limit the impact of fluctuating exchange rates.
Integrating BTC payments into the shopping cart back-end is far more viable, so target the CMS software and payment processors instead of end-businesses. This way, you focus on a few target entities instead of thousands. If even one of them adopts Bitcoin, the others will feel the need to follow suit in order to compete.
This is a great idea! As far as I know, there are even efforts to extend widespread shopping cart solutions with BTC.
Business will be more apt to try Bitcoin if it is available. They will not attempt to "roll their own" solutions.
Well, there are already businesses out there who build their own solutions - my post was meant as an attempt to suggest a proper strategy for doing so.
But this process can of course be sped up through distribution of ready-made solutions.