For the record, I agree with MUCH of what Brice It is saying here. I have been developing Access applications for 15 years and I have EXTREMELY disappointed in the direction the product has taken. Access 2007 is almost unusable for developing software and I am still using 2003 for my clients work. Hopefully 2010 makes it better not worse.
That said...this is truly a remarkable demonstration...if it ends up working that effortlessly then it will be a big success. But sharepoint is WAY to expensive for most of my clients.