Not going to happen anytime soon.
Drive technology is at a standstill. Speeds for CD/DVD drives have been hanging around the same range for years now, and HD's aren't boosting their speed in any significant amount and haven't in years.
Honestly, the difference in bootup speed between my 2.6ghz Intel with a old 150 gigabyte ATA100 drive and my 4200+ with a brand new SATA 250gig NCQ drive is only a couple seconds. There's at least 3 years between the two computers, and no appriciable increase in speed.
We need a new approach to storage, whether it's some form of modified solid state or something brand new. Personally, I suspect the best possible approach would be a solid state setup with a standard HD backup that gets written to independently during downtime when the solid state isn't being accessed. I'm talking gigs of solid state here though.
Because to be honest, there's really not a whole lot else they can do with traditional Hard Drives, at least not at the moment. Solid State is the path of least resistance right now.