DV100HD is max 100megabits per second surely? Hence the name. (plus a bit for audio)
The points you make are valid however. Nobody will get the price break that Apple is getting for a good couple of years (they invested in Samsung a while back). The P2 cards consist of 4 of the fastest SD cards available (very low production yield, hence high price) in a proprietry hardware RAID configuration developed by Panasonic. Pricing will get better over the next few years but there is no doubt Panasonic are gambling the farm on this one. There are competing technologies out there that might kill off the P2 concept before it reaches critical mass.