It's booting!!! After boot, the system recognizes the entire disk. Mounting swap succeeds and it's in the last space on the drive.

Ok, from this, I can draw the following conclusions:
1. The kernel in flash doesn't support >128G drives.
2. The stock kernel on the HDD does.

Is there a way to move the rio partition, or create it earlier on the drive? If I can move it, I can add the largest partition on the end of the disk without changing the partition numbers of the existing partiitions.

With that bit of information, I'm pretty sure I can get this 100% working, one way or another. I attached my boot log for those interested.