I made a new Thread for one of my Cornerless Basses that has Corners but outside Scalloped Blocks.
Thread here.
I have also seen several basses that had single Guitar Ribs but the Top and back had Corners. On the Ribs were glued on external corners across the Ribs. Only on of these I have seen in person. Inside, it looks totally Cornerless Guitar style. Here are a few
borrowed pictures.
I have seen a few others as well with similar external Blocks. One attributed to Testore, one to Montagnana and one just Northern Italy. None of them resembled each other in the actual style of the bass so I would say 4 different makers.
So whether Scalloped blocks externally or full blocks, there is more then one method of making a Cornerless Bass internally or rather, a Guitar model Bass.
To date, I have played each of the 3 styles, two of which I currently own.