Ciao Guido,
check with
Agri-Starts, Inc. They have all kinds of bananas available. With phytosanitary certificate you shouldn't have any problems with EU-customs. You could ask them to use USPS (US Postal Service) for shipping, because they take care of customs procedure. This works quite smoothly here in Greece and also in Germany and I think it should be the same in Italy. The minimum order is 72 pcs, so your friend will have some extra bananas, but they're cheap anyway.
There are also some tissue culture labs in the Netherlands, but I don't know any names, prices and minimum order quantities. But check on google to find maybe any producer in the EU. Please let us Europeans know, if you found any good source.
Greetings from Thessaloniki/Greece