So I want to make a portable HDD with a USB hub and four 1TB USB's with a RAID configuration. I for one have no clue what to encase it in or how, and how to have the USB's in a RAID configuration that works with any device it would plug into?
If you are tying to do it it the way I think you are doing it, it won't work. RAID Requires some kind of Hardware of Software to keep it together. You're best bet is to find a 4 Bay enclosure with USB/eSATA/Network interface that you can carry around with you that does RAID.
I went looking for this answer some time ago also. what I found is that windows has NO SUPPORT for raid of any kind where removable media is involved.
I found that other OS's (notably LINUX) does have the ability to do what you are looking for, but I never bothered to try it.
I agree with drtweak above, a NAS enclosure connected through usb3.0 or network is probably your best bet.
When helping someone else out with a similar issue a few days ago i did stumble upon a 2 bay 2.5 inch hard drive enclosure that is USB and does RAID 1/0. If you want 4 bays you will have to get something a little less portable.