The answer is yes. Infact you could start in Italy at Piombino and take a 20km ferry ride to the island of Elba. Elba is well known of course for the exile of one of Corsica's most famous sons, Napoleon. It has 150km of coastline that can be cycled as well as some hill routes that rise to just over at 1,000m Mount Capanne.
Bastia is just a 50km ferry ride from Elba. From there it is 175km to Bonifacio, Corsica's most southerly port where you can catch a ferry to Santa Teresa on the northern coast of Sardinia. This crossing takes less than an hour. Sardinia, at more than twice the size of Corsica has plenty of riding options. If you ride to the south of the island to Cagliari you can take a ferry to Palermo in Sicily. From Palermo to Messina is around 250km where you can take the short crossing back to the mainland and cycle back to your start point. I have calculated, excluding ferry crossings, that by taking the most direct routes this is some 2,000km of riding! It certainly would be an interesting tour and with some planning could take in some of the routes used by the Tour de France and Giro d'Italia. I sense a book in the offing...
Piombino to Elba with Moby Lines
Elba to Bastia with Corsica Ferries
Bonifacio to Sardinia with Moby Lines
Sardinia to Sicily with Tirrenia
(Note: these are all seasonal services)
Post script - last week I received an email enquiry from a reader in Rio. I have misplaced this so please send again, apologies. Mark