I went through the same journey and had eBay searches for months. I needed one for an N-frame (not nearly as common as the 38/357 stuff). In February I gave up looking and ordered a Ted Blocker with no clips, that way I can use it with any of my speedloader types. The pouch has yet to arrive. I've used Ted Blocker gear in the past and really liked it.
Ted Blocker pouch

 

Have you looked at these:
Jox loader pouches.
And Simply Rugged sidewinder belt pouches.

 

I contacted Jox about a year ago and he said he no longer makes them.
I do have the adjustable Hogue kydex one, it’s cheap and okay.

 

Simply Rugged is good to go. That is my reccomendation.

Solo Speed Loader Pouch - Store - Simply Rugged Holsters

Leather speed loader/moon clip pouch. This is designed to hold one large HKS or *Safariland speed loader. It will also accommodate 2 45 ACP Moon clips (2 stacked in the compartment) Or one 357 x 8 moon clips. It is not intended for concealed carry. If you need to conceal a speed loader or moon...

www.simplyrugged.com

 

Check out the Barranti Leather offering here, their “Barranti Spare.”

Edited to add: I can’t vouch that a Safariland loader would work with this. In addition to the HKS loaders mentioned in the listing, they work with 5-Star brand loaders, too.

Barranti Spare

The Barranti Spare speedloader pouch was built to help conceal the large N frame HKS speedloaders, and works equally well with L and K frame size HKS loaders.

barrantileather.com

 

Check out the Barranti Leather offering here, their “Barranti Spare.”

Edited to add: I can’t vouch that a Safariland loader would work with this. In addition to the HKS loaders mentioned in the listing, they work with 5-Star brand loaders, too.

Barranti Spare

The Barranti Spare speedloader pouch was built to help conceal the large N frame HKS speedloaders, and works equally well with L and K frame size HKS loaders.

barrantileather.com

Ooooo those look pretty sweet.