Grogan, the 5 1/2 ones are more of a problem than the 7 1/2. Yes Rick could probably make a slight variation in the style you have so it would work.
I don't know what style you are referring to but the biggest one that comes to mind is my Cheyenne patterns that are copies of original F.A.Meanea holsters. The 5 1/2 holsters won't work but the 7 1/2 ones will because they moved the top loop down farther on the holster.
I have made those patterns from copying original holsters by tracing and measuring. I'm sure Rick has done the same thing since he owns a few himself.
I have wondered what Meanea did in the day for customers with Remington revolvers, or maybe short barrel Remingtons weren't popular and the 7 1/2 holster just worked and they went with it. Either way I'm yet to see an original Meanea short barrel holster that looks like it will work with a Remington.
It is a problem on the Cheyenne styles because of the recurve in the main seam that locks the pouch in the loops, other Mexican loop styles are not as much problem with the web. Some very contoured Slim Jims can be a problem but most will work with both and any of them can be cut roomy enough to work.
When it comes to custom leather you need to decide the look you want and tell the maker and work out the details on what can be done. When I have a customer order leather for a Remington, some styles are no big deal, but some styles I have to mention the holster shape will vary a little to allow for the web.
I mostly shoot longer barrel Remingtons so most any of my 7 1/2 holsters work anyway.