We only have a couple products and would like the simplicity of a single page for product quantity selection and for checkout, exactly as https://www.ledgerwallet.com/shop is set up. Can Magneto do this?
Looking at the extension marketplace, it is clear that Magneto has affiliate tracking and order tracking that we may eventually implement, hence my reason to use a platform like Magneto for such a simple order/checkout page.
Yes this is possible but it can only be done by customization, The default Magento theme wont allow you to have the ledgerwallet one page website.
You can contact any of the reputed extensions providers to get the quote. Here I can recomend FmeExtensions.com as there per hour rate is comparatively low in the market. They have got 100+ extensions in their store, you can find affiliate extension from them as well,
You need to developed this extension which provides this functinality into same page.
What i suggest you is to use magento standard way for this so instead of all thing in one page, you can use one step checkout extension.
We have develped such extension which can help you: https://www.magecomp.com/magento-one-step-checkout.html