Here is a version that adds initial support for the new grading system:
Sorry for the wait.
Adding grading support was quite a lot of work for us, because of poor design choices by eBay. Instead of leveraging (or perhaps slightly extending) their existing attribute system, they rewrote a functionally identical system from scratch.
So instead of re-using the existing attribute support in GarageSale, we had to write a lot of code to deal with new APIs, to replicate functionality that was already in there.