Indeed, the max speed for a FW800 drive is around 800mbps (I'm not sure if that's bits or bytes, but that aside...) when it comes to FW, it doesn't work quite the same way as you might expect when multiple devices are connected. I could try and explain it, but you'd be better off doing a search online for FW800 protocol, or, "how does FW800 work" to learn more.
That said, and taking your premise into account, here's my analogy for how FW800 [i]doesn't[/i] work:
Let's say you had a flashlight powered by one battery. The bulb glows with a certain amount of brightness. Now you connect another lightbulb to that circuit (in series, e.g., a daisy-chain). Not only would the original bulb glow more dimly (say, half as bright as before) but the second bulb would glow with the same dim light. That's [i]NOT[/i] how FireWire works.
And finally, RAID 0 is not needed. If anything, per the advice I've gotten from friends even more familiar with this stuff than myself, it will only slow down an audio system's performance.
Just one final word... I have a system where I've got 9 hard drives. Many of them are daisy-chained. No performance problems, and I use a LOT of sample-based libraries.