I was thinking more along the lines of cylinder exchanges like propane dealers do. Drop off the empties and pick up a full one.
We had an air club for a couple decades and the local dive shop got it's start using the club compressor and air bank. The club provided the compressor and the shop provided the space, compressor maintenance, and training of new members in tank fill procedures in exchange for the shop's use of the compressor for it rental tanks, non-member customer fills, students, and nitrox fills. A set of fill whips remained outside in a combination lock box allowed for for 24/7 self serve club member air fills. Over the years the funds and some shop investment allowed purchase of a larger compressor and an expanded air bank, so air was never in short supply.
The problem was that the old shop owner sold the shop to a new owner who no longer honored the arrangement and declared that the most recent compressor belonged to the shop - as well as the old compressor and original airbank apparently. Since any paperwork had long since disappeared the club had no real recourse.
This same dive shop under new management also had really crappy evening and weekend hours - not open past 5pm and only open 4 hours on Saturday morning with nothing on Sunday. (They ran a collection agency as their original business and bought the local dive shop, but brought with them their same collection agency customer unfriendly business model.) The problem was that many of the avid divers did not live in the actual city they were located in, but drove there from 50 or so miles away, so they could not drop by over lunch or after work, which meant their only chance to pick up or drop off tanks was on Saturday morning, cutting into prime dive time and making tank rental very problematic as it for all practical purposes involved being charged for a full week. Even for tank owners, given the volume of fills on Saturday morning, the shop would not guarantee fills that day, so you could show up with tanks for the weekend, wait around and not be assured of getting fills.
I figured if they wanted weekends off they could still accommodate divers with drop boxes, either for the diver's tanks or as exchange for rental tanks along the lines you suggested. They ignored the suggestion entirely and also refused to modify their really inconvenient hours.
In the end I just bought my own compressor and chose not to do business with them. I moved away a year or so later, but if I had stayed I had been developing plans to buy a larger compressor and an air bank to start a new air club located near the major dive location in the area (the shop was about 30 minutes away anyway). Then being a bit passive aggressive at heart, I'd have probably expanded it into a small full service shop with weekend hours since I had done the service work for the old shop anyway (before the change in owners).