Nice, but what if you have thousands of products in your shop?
Well I think the best thing would be to just convert your final balance at checkout.
When I'm shopping these days in the US (I'm from Canada), retailers give me the option if I want to be charged in US Dollars, or Canadian Dollars. Retailers should be able to add other options to say Pay in BTC, and they will have the latest conversion price there. The consumer should be smart enough that if they have $100 worth of goods that it'll be approx. 0.1BTC or something like that.