[Valin]

Just reading this week that the wheel was almost unknown in the Muslim world at this time
No flame, BUT I'm gonna need a source on that.

the Sultan asked how much it would cost to replace it
I recall reading this also. If memory serves it was shortly after that the Sultan and the ruling elite started asking why they lost and why they were falling behind the west. At least according to Dr. Bernard Lewis.

[LS]

Hahah. You already have your source! It was Lewis, "The Middle East," toward the end (I have the book at school, so I can't give you the exact page now.)