My DIY raw profile for the D7100 sadly did not work. However, I found a workaround.
The workaround is to use a raw metadata editor to change the metadata to say that it is from the D5200. Then you can import it into LR4 (so far without issues). I used a program called Exif Pilot to edit the metadata. Not sure if it is spyware-free so please do you due diligence before you install it.
UPDATE: I've now been using exiftool. Instructions here: http://betterfamilyphotos.blogspot.com/2013/03/nikon-d7100-tips.html
Nikon D7100 Hands-On Real World User Review
Nikon D7100 Low Light Teaser
Nikon D7100 FAQ and Helpful Links
Nikon D7100 Shadow Recovery
Nikon D7100 Real World Dynamic Range
Nikon D5200 and D7100 Band-Aid: Solutions for Banding
Sample of D7100 banding in a real world shot