Many times we talked about IF it is possible to transform a AR15 to M16.

To me, instead, would be very interesting to know if it is possible to commission to your US gun shop a M16 permanently transformed to a semiauto rifle.

In my country it is not possible to have FA firearms, but let say that to have a original military rifle M16A1 (upper, lower etc etc...) but with only safe and single shot position enabled... As assault weapon I guess such a rifle it would be of NO interest, but for a collector to have in the hands something REALLY MILITARY would be GREAT!

No.

BATF's policy (not the law, but regulatory interpretation thereof) is "once a machinegun, always a machinegun".

Everything except the lower receiver and bolt carrier could be used to assemble a working semiautomatic rifle.  On a bona fide pre-ban lower receiver it would be legal to do so.

You'd have to check with your governments standards on what they consider a "machine gun."

Yes, if you swap out the parts a fully automatic rifle can be made to be fireed only semi auto, BUT is this what the Italian govenment is looking for?  OR is as California Kid says that "Once a machine gun always a machine gun," as it is considered here in the States.