The iFPGA reference is not a joke. That's been in there before. Apple likely prototypes hardware on FPGAs just like any other major consumer electronics manufacturer. Also, before iPad became iPad it was listed as "iProd" in itunes betas.
Its presence is not purely a joke, no, but giving it that name is most certainly a sort of in-joke from an Apple engineer. They could have used any number of other, more generic placeholder names for early device prototyping, but they didn't, because "iFPGA" is a pretty funny notion:
An FPGA is like a Swiss Army knife meant
exclusively for electrical engineers with the knowledge and equipment to give it purpose. And that's fine: if a tool is only useful to a specialist, it's reasonable to design it with the expectation that only a specialist with use it.
Meanwhile, if you think about what Apple's iSomething branding represents (and has always represented) -- consumer devices that bring technology to the masses using simple, elegant designs that anyone can just pick up and use -- then, well, an FPGA is just about the
opposite of that.
And yet, an FPGA chip and an iPad
are similar, through a shared sense of versatility: just as an iPad 'becomes' whatever app you're currently running, an FPGA 'becomes' whatever chip design is currently programmed into it.
So the humour of iFPGA (and yes, I did laugh out loud upon seeing that) comes from the juxtaposition of these ideas. It's
almost entirely inconceivable as a commercial product, but with a tiny shred of plausibility that makes you pause for just a moment and wonder.