There are books on Mt. bike tours in the alps. A friend of mine did the "Trans Alp Tour" that started somewhere in Austria and went to somewhere in Italy over 14 days with upward of 6000' of elevation gain on some days. There is a guide book specifically for this tour. It is easy enough to design you own tour,but it is important to check guide books, because many trails are not open/passable for a mt. bike unless you walk. Switzerland, Italy, Austria and France all have great riding. A store like REI might have some of the tour guide books. Have fun.
Paul