What? No, you don't want to do that. Not even a little bit. In fact none of that makes any sense whatsoever.
8 ssds will be no quicker than 4 and barely quicker than 3. An 8 disk raid 0 is retarded because the odds of it failing are so high.
If you raid 1 the ssds to a hard drive your system will run at the speed of the hard drive instead of the ssds. This would be really daft.
You want three ssds in raid 0 and a nightly backup to a normal hard drive, combined with making an image of the drives after you first install everything.
I hope you have a good reason for asking such a question, it looks like a wind up.