Since WorldWinds (the Windsurfing Concessionare at Bird Island Basin in the So. Padre Island National
Seashore) is a Starboard dealer, and they have rentals, I would check with them first and see if they have a Kode Tufskin 137 your wife could try out.
If she can get it going, rent it for the day and see if she still likes it.
They have a large selection fo 2011,2010 and even some 2009 boards to choose from, so take a trip to Worldwinds and see what they have than gives your wife the stability she needs.
What displacement board was she sailing..... were the lessons from the guys at Worldwinds?
Hope this helps,