Well, whether it's really an option depends on your luck finding someone willing to make it. I doubt Jim is offering to sell these (Jim,please correct me if that's wrong).

Most other builders will be put off by the challenge of making those clamps, which are clamping to the blade where it's still oval and tapering. I expect that is very finicky work, unless Jim has some shortcut. It definitely can't be done without the builder having your fork in his hands, because every fork will be slightly different at that point.

I would caution any wannabee rack builders to go a more standard way for your first few racks, don't try Jim's way until you have achieved mastery!