Hi DNNers!

I'm new here and I'm evaluating DNN Community Edition for the purpose of creating a complex website for a non-profit organization with extremely limited budget. One of the main issues is user permissions. We need extremely granular and detailed user permissions for custom usergroups (and override some of those for individual users, even). But as I see in the "edition comparison", this seems to be only possible within the Professional Edition, which is way beyond our budget limit. Specifically I'm looking for how to do these things:

1. A "file central" where logged in users can upload and manage files, pretty much like "Windows Explorer", but just web-based. They should be able to set "read" or "read/write" permissions per file for every usergroup. Example A: Upload a public flyer (PDF), say "READ is public (even for not-logged-in website visitors, WRITE is only for usergroup 50 and above". Example B: Upload a meeting protocol (*.doc), say "READ is only for usergroup 30 and above, WRITE is only for usergroup 60 and above plus specific user XY".

2. We want to use an external MSSQL Database (it's on the same instance of MSSQL, just a separate database) where we have custom data in relational tables (with foreign key contraints) and views. Logged in users should be able to view and modify that data in a master/detail style with grids and/or forms, where some fields of that forms should fetch "sub-data" from other tables and let the user choose such data in comboboxes within the forms. I have found this module http://store.dotnetnuke.com/home/prod... which might serve that purpose. But still, similar like in the examples above, we would need detailed settings for user permissions per row on those custom tables too.

What module do you recommend for "1."? What module do you recommend for "2." (Is the one that I found good for this?)? How to meet that requirement for all these detailed userrights within the Community Edition? Is there a module/extension that offers this functionality, so that all the other (3rd party) modules can make use of / are aware of that extended userrights/-permissions functionality too?

Thanks in advance.