I would like to see you download and host the software catalog on your own servers. One of the only issues we run into with this solution is that many times when we add a new product, I have to do the firewall dance with our networking team to allow the new source URL for an update/application. We strictly geo-block anything outside of countries where we do business and some of these source files are hosted all over.
Additionally, we may be blocking a particular domain so that users cannot directly download an installer/update to force them into SCCM to get their applications.
Re-hosting the catalog on your own infrastructure would allow customers to open a connection to a specific, trusted location rather than having to potentially manage firewall rules for hundreds of products.
Other than the infrastructure, this doesn't seem like it would add much to the processes PatchMyPC are doing today. You guys already download the source files and upload to virustotal. Seems like once that comes back good, the file could then be moved to your own web server so that we can consume it directly from you.