One of the members on this forum has made a taller bracket which simply replaces the stock Honda one. This new bracket raises the Honda backrest I believe 3" and makes it more user friendly.
Now here are my findings: I cut some 3/8 steel gas pipe to 4" lengths. I ordered two motor studs long enough to accommodate the 4" sections of pipe and still leave enough thread for nuts. Removed backrest via two bolts, installed two studs, dropped two 4" sections of pipe over studs, reattached backrest with self locking nuts. Way better for Mrs than stock BUT still lacking in support should she want to lean back.

So the ONLY option currently available is the Corbin stand alone which is 14" wide and 12" tall, slightly better and more useable angle.

Now here is a real interesting ALTERNATIVE. Buy another Utopia backrest. Using "Ultimates" extension bracket and bolt the Utopia to that, tada fixed. Your Mrs will have a larger backrest and it will be fully adjustable.