I would be interested in having a feature/function of pre filling CloudFlare’s cache rather than on-demand caching. I would be willing to pay for this per-use.
A client hosts a site from China. They are not willing to change hosting provider, but are willing to use CloudFlare. I would set up the account, and pay $x for CloudFlare to index the site and cache the resources globally (or at least somewhere in CF’s fast network, outside of China).
Every user gets a fast experience of every resource request.
One more thought… a sub option to point CF to sitemap.xml urls rather than spidering - assuming the xml files has images in additional to pages.