Hard to make a specific recommendation, since 1.9 is not released yet, and this is all new code so very few people will be familiar with it. However, I have looked at it a bit and it is mostly nice new clean code, so any decent Moodle developer should be up to the task.
The generic answer to this sort of question is to look up your friendly local Moodle Partner. The provide Moodle services including custom development, and donate a part of their revenues back to moodle.com to fund future development. You can find a list here: http://moodle.com/partners/list/
It might also be worth contacting Nicolas Connault or Petr Skoda. They are both work for Martin Dougiamas (although they live in Europe) and did a lot of the work implementing the gradebook. They may possibly have the time and inclination to write a custom gradebook report.
Gradebook
Export quiz results of all courses in one excel file
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