In Guy Gibson's splendid book Enemy Coast Ahead (chapter 5, I think), he mentions successfuly dive bombing in a Hampden. A 60 deg dive fom 6,000 ft pulling out at 2,000 ft. He doesn't mention the speed on pull out but he does record that the perspex nose often collapsed "much to the embarrassment of the bomb aimer". I'm sure he mentions trying it again in a Lancaster but I'm damned if I can find my copy.
Just a thought; I remember seeing Shackleton displays that featured a steep descent in coarse pitch. OK, nothing approaching 60 deg but would the props have acted as effective air brakes on a Lancaster with just the 12 blades?