Con someone comment if Kindle is available in Europe? Does whispernet work there? What countries? I can easily imagine why whispernet is such a great success in USA, but it really, really depends on network working anywhere you are.
Modular design for eReader is very good idea. It would allow people to choose what they want / need - for example, you want touchscreen, but you don't need wifi and 3G, so these modules won't be included in your purchase. Someone else want wifi, not 3G, and there will be some who want 3G and not wifi.
I fear that in many Europe countries, 3G is far from ideal solution.
In fact there isn't any ideal solution, because there is no free worldwide "datanet" yet (I hope you all read your daily portion of Peter F. Hamilton
), so we have to survive with what we have now.