It has probably been discussed before, although I do not remember it clearly. It may be that guy in the U.S. who's doing that, his custom DE handles and razors are known as Bull Mastiff. He went through a difficult time earlier this year and reportedly shut the operation down, although reports now indicate he's back in business.
What is more widely available is a ready-made Progress with a metal knob, the so called "Mergress". This is available in standard but also long handle version. Few members here do have this razor, they have obtained it from the U.S.
The vendor selling it there is "Lee's razors" (dot com). He has few of those every now and then, but they go relatively fast. Therefore is it advisable to give Lee a call as reportedly he usually keeps a couple aside (I know of one member here who obtained his Mergress that way). It is a very nice razor, better looking than the standard Progress, but for many having to go through all that and then through customs in the UK they don't bother with getting a Mergress.
If you search the forum you may find pictures as well, although i would think Lee's website should have at least one as well.
