Weird time-shifting subscriptions

We're putting together an unusual subscription-based site, which will work more like a serialized training course than traditional magazine-style subscription. Instead of all subscribers receiving/accessing the same content at the same time, every new subscriber (no matter when they subscribe) will start at issue #1, then issue #2 a week later and so on. That's where the weird time-shifting comes in. . .

So here's where we're at: There are 26 issues, so we've created 26 subscriber roles. Using Content Access module, each issue will be restricted to one subscriber role (eg issue #1 is restricted to "issue 1 subscriber" role, etc). We're using Ubercart to sell the first subscriber role. Then, using Administer Users by Role module, we can upgrade subscriber roles each week (eg "issue 1 subscriber" becomes "issue 2 subscriber", etc).

It works but I keep thinking there must be a better, more automated way -- but I've looked through a lot of Drupal modules and forum topics. I've also looked at various other LMSes, CMSes and shopping carts, which could possibly do the job -- but I'm determined to stay with Drupal. This search has reinforced to me just how good Drupal and many of its modules are.

I'd create a module if I had the time and expertise, but unfortunately I don't have either.

Does anyone have any other better ideas? Potentially, a solution could be useful to a lot of people. Online training comes to mind . . .