Dimension instrument load time versus Hypersonic's

I need load times of less than 1 second for 100MB sfz files. Is that possible?

Sure. Just load from a virtual disk.

I hear Apple will be shipping notebooks with flash drive hard drives this fall
they cost some, but Apple users are used to that

for the rest of us
I envision a usb hub in the shape of a sphere with 80 or so thumb drives are all lit up
you buy as many as you can afford as you go

A virtual disk is a not-physical disk. Using several programs you can create a disk in the memory of your PC, or in another PC in the network, if you have one.

You can mount a small routine which fills your virtual disk from the hard disk when you turn your computer on, let's say, when you go for coffee. For instance, if you have 2GB of memory you can dedicate 1GB tp the virtual disk. Then, you can have the frequently used Dimension Pro sfz files in that disk. The loading times from there can be 1/5th of the hard disk times. I have seen several users who do this, not only for Dimension Pro but for Kontakt and other samples where you can relocate contents.

The virtual disks can also be in another computer, and you can access to those via fast networking (i.e. gigabit Ethernet). The network components can become a bit expensive, but who cares about price when it's about avoiding creativity losses.

If this doesn't work for you, and you really need those 100MB per second, you can consider disk-streaming solutions such as Kontakt or Gigastudio. Those will load only a very small part of the sample in memory, and then they will stream the rest from disk.