Seatpost racks may be OK for ATB's with heavy gauge seatposts, but on a true racing bike, I'd be worried that the post will get bent.
Now, if you are considering touring in Europe, many hotels offer baggage forwarding services. People have been doing walking pilgramages in places like France for many, many years, and many good hotels will send your bags to the next hotel on your itinerary, and they will be waiting in your room when you arrive. All you need to carry, then, is repair stuff.