Andy;
Galco makes an inexpensive shoulder holster that seems pretty good. Maybe they make one for your pistol.
Click on: Galco holsters; Holsters; Gun holster, pistol holsters, western holsters, shoulder holsters, leather holster and Glock holsters
Send a PM to Old Padawan (his name is Bill), here on this forum. He works for Galco, and knows all of their products.

I don't believe that you will find anything in leather that will be as inexpensive as your G.I. shoulder rig was.
However, since speed and holster-fit are not issues for you, maybe a Nylon-fabric rig would do the job at a very reasonable price. Maybe Uncle Mike's?

You could also buy a belt holster (Galco, once again, makes good soft-leather, inexpensive ones) and add G.I.-style shoulder straps to it. Any shoe-repair shop could sew them on.

I retired many years ago, so I am not current with what's available from whom.

Thanks for the leads...

You suggested cbLeatherworks on a different thread, so I sent an email to chuck, asking if he would be interested in putting something together for me. I sent him some pictures of my old rig and asked him about a knock-off of the old military design or maybe a custom vertical holster hanging from a standard X-back strap system. I know it may not be cheap, but I will use it alot.

I'll PM Bill to see what he suggests,

Andy