One solution to the current backlog would be to give the user more control over their instrument pages.
So they can autonomously upload, create the page, we’re all used to editing headers, etc. already on Soundcloud and server-side scripts can easily conform photos, recolour them, etc. to fit with the branding.
Once the ‘user completes their instrument page (in a draft mode), it is added to a queue for approval before it goes live.
Some of the more experienced users could be given extra powers to test and approve new submissions.