I have found the info that I needed in the second part of the article "I progetti Piaggio-Casiraghi", published in
"AeroFan n.65, apr.-giu. 1998" (its text is in Italian and English). There are 3-views and photos of the wind-tunnel models or mock-ups of many ing.Casiraghi's projects, included the P.133 and P.127 (but also other strategic bombers as the P.123, the P.130 and, in the issue n.64, the P.112 and P.114).
The Regia Aeronautica had ordered the production of 24 P.133 (MM 26248-26271), of them 6 were under construction on 8 Sept. 1943. There was also a project for a pressurized civil transport version, the P.133C.
The P.127 was a huge transport aircraft (wingspan: 56m, max weight: 56,000 kg) with 6 x 2000 hp engines, 2 in the outer wings alone, and 4 paired (2 per each wing) moving counter-rotating propellers. The civil version (P.127C) could transport 40 passengers over the Atlantic; it was pressurized. In the article there aren't details about a possible bomber version of it.