Did more searching within this thread. Some say that TA04, TB Evo3, 416, 418, 419 steering racks fit. So that's promising.
Wondering if this might fit. Seems like the same fore-aft arm design like the 414M (ie: no 90º arm on the right side for servo); but with longer and curved extensions.
http://www.ebay.com/itm/251468195994...AIT&rmvSB=true