any updates? Do the roots look like they took?

Since this thread really ought to have a link to the other thread:
http://bonsaistudygroup.com/trident-maple-discussion/new-trident-full-of-options/

As mentioned, its just now showing signs of thriving so I haven't messed with the roots any.  I suspect this new vigor is a good sign, though not necessarily indicative that the grafts have taken.

It certainly didn't kill the tree, but in hindsight it was too drastic a reduction.  The tree sulked most of that year and took a little while to get going this past year ...while never getting a full head of steam.  I plan to repot it this spring and hope to be able to tell you that all the grafts took ...or at least that there's an awesome nebari just waiting to grow into its own. 

We'll see.