Apple motherboards are Intel (reference) motherboards that are rejiggered to Apple specifications. Plus a few interesting chips may be added. Intel has FoxConn do the actual manufacturing of Intel mobos and Apple likely would do the same for its Intel mobos.
http://www.atomicmpc.com.au/News/148502,intelfoxconn-alliance-could-cripple-asus.aspx
No, they are not. We have gone around and around about this before. You make your assertions that Apple does not do the engineering, just buying off the shelf generic stuff and tweaks it... without knowing what you are talking about. And then blather about "Jesse Jobs Gang" and over priced junk. I'd suggest the others just not bother engaging you on this. It's a waste of time... after several years of repeatedly engaging you in the SAME OLD, SAME OLD, I know.
All x86 motherboards are in some way Intel reference motherboards -- otherwise they wouldn't be compatible.
Apple designs their own Intel-based motherboards (based on Intel standards as all do), their ARM motherboards completely, and even designs their own ARM chips (based on an ARM core standard, as all do). The Chinese/Taiwanese just produce to Apple's specs, and they often have to re-do their manufacturing in order to be able to handle Apple's specs.
In fact, news came out that Apple has a habit of heavily investing in Chinese factories, building them out, modernizing, making them capable of producing Apple products. Then Apple gets exclusivity and a cut rate on the initial couple years' run.