This is a tough question to answer. This laptop doesn't come out until tomorrow so reviews are hard to find. I looked on HP's spec sheet (
Here) and I don't see any mention of an additional hard drive bay so I don't think it will support any RAID setup.
Do you really need a RAID setup anyway? RAIDs increase throughput not IOPS. They are great if you need to be able to quickly write and read large files but for an average user IOPS is the number that is more important for subjective performance.
In that regard, any SF-1200 based SSD will be excellent. However, I wouldn't recommend the C300. Don't get me wrong, it is one of the best drives around right now but many of those benefits are because it uses SATA 6.0Gbps. I don't believe that the dv7-4290us has SATA 6.0Gbps (I could be wrong. Again, the lack of reviews is making this difficult) so the C300 would operate at SATA 3.0Gbps and you wouldn't see any advantage over other SF-1200 based SSDs.
You could also consider waiting for the newer SF-2000 based SSDs but I don't believe those will be out for about 6 months...
Hope some of this helps!