raid 10 is probably what your after. it has the benefits of raid 0 with the redundancy of raid 1.
problem is there is no raid array that works in the way you want.
raid 10 mirrors the raid 0 drives there and then. it doesnt wait till a set time to do it.
i dont mind when it backs up or what it does. as long as i dont loose all my data if one ssd gives out :P how would i set something like that up?