Its quite common, I have one for example.

Only the Lenovo W series supports RAID afaik.

My laptop is an Asus g7. A college of mine did some tricks to get a RAID0 in his macbook pro. The future is now.

I know, I was waiting. I have the optibay in MBP15 with a rotational disk for backups since SSDs have been so unreliable. The 1TB samsung has been amazing. You are correct, I should swap out the 1TB rotational for another 1TB and run RAID.

At this point you'll probably get the most increased performance by upgrading your MBP rather than RAID its storage.

I do want more Performance, but I really want more and faster storage so I think RAIDing another 1TB SSD is in order. And I couldn't get this with a new MBP. I think they only will accept a single PCIe drive.