We're also keen to know, as we launched an app to handle archiving of products mere weeks before Shopify announced they are finally bringing out this feature. We have since removed the app from the App Store on the basis that Shopify were going to have this feature soon but it's been a lot longer than expected. Perhaps we should have kept the app going. We are continuing to rework the app's functionality to enhance their built-in archiving feature, when it's finally available.
Unfortunately Shopify killed the app with the announcement of their own Archive feature, as it essentially negates the need for the app. We ceased further development of the app at that point and delisted it from the store. We are going are planning strip away any archive processing, and leave a similar (but differently implemented) alternative products feature. Additionally, we are going to have an "auto-suggest" feature to provide you with a list of suggested products to archive, based on some criteria. You will be able to "select all" or choose which of the suggested items should be archived but only if Shopify make archiving a feature of the APIs. If they don't open this to the APIs, we can at least provide suggestions, with a direct link to the product's admin page, making It a little easier to find products to archive, and then archive them.
Just to let you know, we've rebranded our archive app having stripped away any "archive" related features, since this will all be covered by Shopify's archive product feature when it launches.
The app is now known as Alternative Products and helps you to easily set up alternative products on your old / discontinued / archived products - Stop wasting the traffic coming to your old product pages, and direct customers to a newer model or similar product that you do still sell.
Any feedback is very much welcome. Hopefully the app will do well after being initially being scrapped due to Shopify announcing it is finally releasing this much needed feature.
Alternative Products App Store listing