Parsing wowhead actually is trivial for models. You can use Chrome/IE/Firefox inspector network tab or any HTTP inspection when you click on "View in 3D". Use the filter box to filter HTTP traffic for "modelviewer", and you will see that the modelviewer will load a JSON(JavaScript Object Notation) file, then from the JSON a mo3 file(model), a png file for the texture and a png file for the alpha channel.
For weapons/shields/offhands parsing it is fairly easy, but for armor each gender+race combination usually has a different model file, where the png texture is being stretched around it using PIPs(points in polygon).
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However, if you can figure out how to extract model paths from the client then that is your best bet, as
unsolicited parsing (without written permission) is
really not nice!
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You could also try asking
Aelobin(
curse), because AFAIK he is the original author.