Not to say that they don't exist.. in fact, I could swear I've seen reference to a scratch-built one on a heavily modified race car somewhere, but you'll find some information in this thread:
For what it's worth, "Legend" and "DLF" who are both referred to in that thread, absolutely know their stuff. DLF has quite a few write-ups here that are considered the "gold standard" for a particular process.
AJE made one and it is for sale, a number of people run them in their Thunderbirds. I haven't heard much good about them for street driven cars, but not sure what the point of them are besides less weight and ability to run bigger oil pans.
Would that fit a Mark8 well?I would think if one could simply order them many would have done it by now. I knw a few knowledgeable people have tried custom ones but they never turned out successful.