Here's the Sparviero and the Aquila, two conversion of the sister-liners Roma and Augustus built in 1926. Several proposals were made by several people from 36 till about 41 and 42.
What I have on the Sparviero is the 1936 design of converting the diesel-powered Augustus into an auxiliary carrier. I have no info on air group, and speculation of what could be used is rather pointless outside of an AU-version, since such speculation would not be prudent for a never-were. The conversion keeps most of the hull and propulsion intact, with the superstructur razed to accomodate the flight deck. Bulges were added to increase stability and survivability, her speed dropped below the original 20kts. The flight deck itself is not full length, terminating before the stern and extending slightly past the stem. There are no catapults and the deck would have two elevators. Sources I have indicate an air-groupd of 24-36 fighters and 9 torpedo bombers. Armament is very light, with 8x4" guns that were essentially Italian copies of the British late-WW1/post-war AA guns. Written sources state there were to be 6" guns mounted as well, but nothing I've seen give any indication that there were any, as only the 4" guns are shown.
1936 design for the Sparviero
In 1941 designs were made for converting the liner Roma into an aircraft carrier. She was renamed from Roma to Aquila since there already was a battleship Roma on the way. The entire superstructure was stripped, the bow rebuilt and the counter-stern filled in, creating a more modern looking hull. Her entire amid-ships are was gutted, with all boilers and engines removed, and replaced with the boilers and turbines from two Capitani Romani class destroyer leaders. Her speed would have been 30kts. Sponsons were made for all of the guns, the funnel and the island to make more space on the flight deck. The catapults meant for the sister-ship of the Graf Zeppelin was put onthe Aquila. Rather large bulges were added to increase stability, and add some semblance of torpedo protection.
Her armament consisted of 8x135mm guns in single mounts, 12x65mm AA guns in single mounts and 23x20mm sixtuple mounts. Her air-group were to consist of 51 Reggiane Re.2001 Delta fighter-bombers, serving as both the fighter and torpedo bomber. There were 26 planes inside the hangar, 15 planes suspended from the ceiling, and 10 parked permanently on the deck. A wing-folding version of the Re.2001 was to be developed, but never made that would increase the air-croup to a total of 66 planes.
As was the case with so many of Italy's most promising projects, delays due to the war, Allied bombing, signing of the armistice and capture by the Germans made sure that none of these projects saw completion. Plans were proposed to finish her post-war, but came to naught.
Aquila as projected upon completion in 1943: