PDF plugin

I’m setting up a site w/ membership option. Plan on uploading a lot of individual pdf’s (hand-writing, workbook pages and illustrations). My uploads would be all over the place (no structure)…

Is there a plug-in for the front-end where registered users could check off downloads as they went along – so they could easily see what’s “new”? Like a checkbox? Something that would keep track along the way (when logged in).

Or…..if anyone has any ideas on how I could achieve something similar.
I’m open to any ideas. Thanks MUCH.

*I saw “Front-End Checklist” which is great but only allows for 50 checkmarks. Won’t work.