Honestly, we used to run CO2 rigs like that all the time. The old remote rigs were great if you had a gas hog that needed a big tank, and particularly good for Automags which were real finicky if they got liquid into them. Some of the big early HPA tanks were run on a remote rig too, mostly because of their bulk and weight on something like a 3k/114ci tank.
Not sure how the scott packs are run, but the best method is to have a regulator right at the tank so that you can run just the operating pressure through the lines. Put a check valve disconnect at the gun input, and off you go. Just don't remember if you needed an additional chamber at the gun on an HPA remote or not to act as a buffer.... it's been a long time.
But any shop with an old school airsmith should be able to set you up no problem. May just have to order some parts, doubt they stock it much these days.