The X1, the SD1, SD5 and the Midjay plus all the Yamaha Tyros line had hard drives.
I agree it would be nice to be able to swap quickly, but I'm just saying I've never had one fail. Hope I never do!
I'll have my E50 and/or laptop on hand if it ever happens on a job. Not ideal of course, but you must have backup of some sort.
DonM