Boot-cycle laptops? The only times I ever reboot mine fully is when something crashes really hard (and is usually followed by days of diagnosis to stop it happening again). Laptops brought this amazing thing called "suspend" and "hibernate" to the user's attention, and it's now an option on every shutdown dialog on every operating system in common use.
My laptop is XP too, so the "uptime" of the single session that's been running on it for months a time is huge and quite impressive by now - XP isn't the most stable of OS but it obviously still pretty damn good, without ever seeing a BIOS screen in the meantime (I much prefer suspend because it can last being "off" all day and it's rare that the laptop is off for more than an entire day, and it resumes instantly).
More importantly - why not just have the SSD-caching HDD's that are coming out now and fit in a single 2.5" drive and would presumably take a lot less power? Or just two HDD's in a RAID setup? Dual drives in a laptop just sounds like the perfect way to increase power, costs and component count, i.e. things to potentially break, without getting much benefit for it. Gimme a laptop with two drives and I'll stick two SSD-caching HDD's in there, mirroring each other - and get better power consumption, better data security and probably cheaper too.