Here are a couple of other large cultivars, which have been circulating for many years before the "B52" -- including the "Southwest Giant" (aka "Slack's Giant" and "G16"), attributed to Adrian Slack and his Marston Exotics nursery back in the 1980s, and "Dirk Ventham's Giant," (aka "G14") also originally attributed to Slack. Both are seen here with their first large Spring leaves, approximately 3.8 cm (1.5") in length.
Back in 1998, I crossed one of the "Southwest Giants" with a "B52" but it will be some time before I know whether that F1 generation carries that large trap trait . . .
Dionaea muscipula cv. "Southwest Giant"
Dionaea muscipula cv. "Dirk Ventham's Giant"