I need an adapter like this:

Manfrotto 186 Female Threaded 3/8" to Male 5/8" 186

But it needs to be 5/8 female threaded to 5/8 stud. Can't find one.

The standard for that is going to be 3/8" on the threaded side. If you went with a 5/8" thread, the body would have to be larger to make it work. I did a quick search of the popular pro grip sites and I found 3/8" but nothing larger.

Is there a reason you need a 5/8" thread?

A machine shop with a lathe can certainly make these for you. It may be cheaper and easier to adapt the incoming connector to 3/8" though.

I have a mic stand with a shallow 5/8 male top thread, and I wanted to use it as a light stand. I have a 3/8 female to stud adapter. Finally decided to use 2 adapters, the one I have with a 5/8 female/3/8 male adapter.

Ah.. So that complicates things a bit more since the 5/8" mic thread has a very shallow pitch (27 tpi) versus the normal 5/8" with 18 tpi.

You are going in the best direction in using a thread adapter.

Is this the one you picked out??

On-Stage MA100 - Screw Adapter MA100 B&H Photo Video

Very similar, but bought on eBay. I may add a rubber washer between the two adapters.